diff --git a/src/bindings/fluid_cmd.c b/src/bindings/fluid_cmd.c
index a45eba97..63bb2915 100644
--- a/src/bindings/fluid_cmd.c
+++ b/src/bindings/fluid_cmd.c
@@ -18,12 +18,10 @@
  * 02110-1301, USA
  */
 
-#include "fluidsynth_priv.h"
 #include "fluid_cmd.h"
 #include "fluid_synth.h"
 #include "fluid_settings.h"
 #include "fluid_hash.h"
-#include "fluid_sys.h"
 #include "fluid_midi_router.h"
 #include "fluid_sfont.h"
 #include "fluid_chan.h"
diff --git a/src/bindings/fluid_cmd.h b/src/bindings/fluid_cmd.h
index 7e81ab08..b3df00d2 100644
--- a/src/bindings/fluid_cmd.h
+++ b/src/bindings/fluid_cmd.h
@@ -21,7 +21,7 @@
 #ifndef _FLUID_CMD_H
 #define _FLUID_CMD_H
 
-#include "fluidsynth_priv.h"
+#include "fluid_sys.h"
 
 
 void fluid_shell_settings(fluid_settings_t *settings);
diff --git a/src/bindings/fluid_rtkit.c b/src/bindings/fluid_rtkit.c
index 282a4014..55be6149 100644
--- a/src/bindings/fluid_rtkit.c
+++ b/src/bindings/fluid_rtkit.c
@@ -25,7 +25,7 @@
   SOFTWARE.
 ***/
 
-#include "fluidsynth_priv.h"
+#include "fluid_sys.h"
 
 #ifdef DBUS_SUPPORT
 
diff --git a/src/drivers/fluid_adriver.c b/src/drivers/fluid_adriver.c
index f1ab772a..4311c46f 100644
--- a/src/drivers/fluid_adriver.c
+++ b/src/drivers/fluid_adriver.c
@@ -19,6 +19,7 @@
  */
 
 #include "fluid_adriver.h"
+#include "fluid_sys.h"
 #include "fluid_settings.h"
 
 /*
diff --git a/src/drivers/fluid_adriver.h b/src/drivers/fluid_adriver.h
index 1564168f..5cfc688b 100644
--- a/src/drivers/fluid_adriver.h
+++ b/src/drivers/fluid_adriver.h
@@ -21,7 +21,7 @@
 #ifndef _FLUID_AUDRIVER_H
 #define _FLUID_AUDRIVER_H
 
-#include "fluid_sys.h"
+#include "fluidsynth_priv.h"
 
 /*
  * fluid_audio_driver_t
diff --git a/src/drivers/fluid_coreaudio.c b/src/drivers/fluid_coreaudio.c
index 56860701..baeada53 100644
--- a/src/drivers/fluid_coreaudio.c
+++ b/src/drivers/fluid_coreaudio.c
@@ -24,12 +24,16 @@
  *
  */
 
-#include "fluid_synth.h"
-#include "fluid_midi.h"
 #include "fluid_adriver.h"
-#include "fluid_mdriver.h"
 #include "fluid_settings.h"
 
+/* 
+ * !!! Make sure that no include above includes <netinet/tcp.h> !!!
+ * It #defines some macros that collide with enum definitions of OpenTransportProviders.h, which is included from OSServices.h, included from CoreServices.h
+ * 
+ * https://trac.macports.org/ticket/36962
+ */
+
 #if COREAUDIO_SUPPORT
 #include <CoreServices/CoreServices.h>
 #include <CoreAudio/CoreAudioTypes.h>
diff --git a/src/fluidsynth.c b/src/fluidsynth.c
index 16eafb3c..7bd6cdf6 100644
--- a/src/fluidsynth.c
+++ b/src/fluidsynth.c
@@ -18,13 +18,7 @@
  * 02110-1301, USA
  */
 
-#include "config.h"
-
-#include <stdlib.h>
-#include <stdio.h>
-#include <string.h>
-
-#include "fluidsynth_priv.h"
+#include "fluid_sys.h"
 
 #if !defined(WIN32) && !defined(MACINTOSH)
 #define _GNU_SOURCE
@@ -35,8 +29,6 @@
 #define GETOPT_SUPPORT 1
 #endif
 
-#include "fluidsynth.h"
-
 #include "fluid_lash.h"
 
 
diff --git a/src/midi/fluid_midi.c b/src/midi/fluid_midi.c
index fb71a822..38c2bf6e 100644
--- a/src/midi/fluid_midi.c
+++ b/src/midi/fluid_midi.c
@@ -34,6 +34,7 @@ static long fluid_getlength(unsigned char *s);
  * Note: This rewinds the file to the start before reading.
  * Returns NULL if there was an error reading or allocating memory.
  */
+typedef FILE  *fluid_file;
 static char *fluid_file_read_full(fluid_file fp, size_t *length);
 static void fluid_midi_event_set_sysex_LOCAL(fluid_midi_event_t *evt, int type, void *data, int size, int dynamic);
 static void fluid_midi_event_get_sysex_LOCAL(fluid_midi_event_t *evt, void **data, int *size);
diff --git a/src/rvoice/fluid_rvoice_dsp.c b/src/rvoice/fluid_rvoice_dsp.c
index 25f4a4b8..aec79aab 100644
--- a/src/rvoice/fluid_rvoice_dsp.c
+++ b/src/rvoice/fluid_rvoice_dsp.c
@@ -18,10 +18,9 @@
  * 02110-1301, USA
  */
 
-#include "fluidsynth_priv.h"
+#include "fluid_sys.h"
 #include "fluid_phase.h"
 #include "fluid_rvoice.h"
-#include "fluid_sys.h"
 #include "fluid_rvoice_dsp_tables.c"
 
 /* Purpose:
diff --git a/src/rvoice/fluid_rvoice_mixer.c b/src/rvoice/fluid_rvoice_mixer.c
index af0ef75d..85c3fb91 100644
--- a/src/rvoice/fluid_rvoice_mixer.c
+++ b/src/rvoice/fluid_rvoice_mixer.c
@@ -23,7 +23,6 @@
 #include "fluid_sys.h"
 #include "fluid_rev.h"
 #include "fluid_chorus.h"
-#include "fluidsynth_priv.h"
 #include "fluid_ladspa.h"
 #include "fluid_synth.h"
 
diff --git a/src/sfloader/fluid_samplecache.c b/src/sfloader/fluid_samplecache.c
index 036964f5..f464f178 100644
--- a/src/sfloader/fluid_samplecache.c
+++ b/src/sfloader/fluid_samplecache.c
@@ -29,7 +29,6 @@
 
 #include "fluid_samplecache.h"
 #include "fluid_sys.h"
-#include "fluidsynth.h"
 #include "fluid_list.h"
 
 
diff --git a/src/synth/fluid_tuning.c b/src/synth/fluid_tuning.c
index ee083116..0df248b7 100644
--- a/src/synth/fluid_tuning.c
+++ b/src/synth/fluid_tuning.c
@@ -20,7 +20,6 @@
 
 
 #include "fluid_tuning.h"
-#include "fluidsynth_priv.h"
 #include "fluid_sys.h"
 
 
diff --git a/src/synth/fluid_voice.c b/src/synth/fluid_voice.c
index 2bbe5de2..ab48b4e8 100644
--- a/src/synth/fluid_voice.c
+++ b/src/synth/fluid_voice.c
@@ -18,7 +18,7 @@
  * 02110-1301, USA
  */
 
-#include "fluidsynth_priv.h"
+#include "fluid_sys.h"
 #include "fluid_voice.h"
 #include "fluid_mod.h"
 #include "fluid_chan.h"
diff --git a/src/synth/fluid_voice.h b/src/synth/fluid_voice.h
index 6038a1a9..386f70e7 100644
--- a/src/synth/fluid_voice.h
+++ b/src/synth/fluid_voice.h
@@ -30,7 +30,6 @@
 #include "fluid_lfo.h"
 #include "fluid_rvoice.h"
 #include "fluid_rvoice_event.h"
-#include "fluid_sys.h"
 
 #define NO_CHANNEL             0xff
 
diff --git a/src/utils/fluid_conv.c b/src/utils/fluid_conv.c
index 483b371d..6e169b03 100644
--- a/src/utils/fluid_conv.c
+++ b/src/utils/fluid_conv.c
@@ -19,6 +19,7 @@
  */
 
 #include "fluid_conv.h"
+#include "fluid_sys.h"
 #include "fluid_conv_tables.c"
 
 /*
diff --git a/src/utils/fluid_hash.c b/src/utils/fluid_hash.c
index 37b0a06a..946a873b 100644
--- a/src/utils/fluid_hash.c
+++ b/src/utils/fluid_hash.c
@@ -31,7 +31,7 @@
  * MT safe
  */
 
-#include "fluidsynth_priv.h"
+#include "fluid_sys.h"
 #include "fluid_hash.h"
 #include "fluid_list.h"
 
diff --git a/src/utils/fluid_ringbuffer.c b/src/utils/fluid_ringbuffer.c
index 71fd1e48..e6720011 100644
--- a/src/utils/fluid_ringbuffer.c
+++ b/src/utils/fluid_ringbuffer.c
@@ -24,7 +24,7 @@
  */
 
 #include "fluid_ringbuffer.h"
-#include "fluidsynth_priv.h"
+#include "fluid_sys.h"
 
 
 /**
diff --git a/src/utils/fluid_sys.h b/src/utils/fluid_sys.h
index 10f7d12b..72ca197e 100644
--- a/src/utils/fluid_sys.h
+++ b/src/utils/fluid_sys.h
@@ -20,17 +20,20 @@
 
 
 /**
-
-   This header contains a bunch of (mostly) system and machine
-   dependent functions:
-
-   - timers
-   - current time in milliseconds and microseconds
-   - debug logging
-   - profiling
-   - memory locking
-   - checking for floating point exceptions
-
+ * @file fluid_sys.h
+ *
+ * This header contains a bunch of (mostly) system and machine
+ * dependent functions:
+ *
+ * - timers
+ * - current time in milliseconds and microseconds
+ * - debug logging
+ * - profiling
+ * - memory locking
+ * - checking for floating point exceptions
+ *
+ * fluidsynth's wrapper OSAL so to say; include it in .c files, be careful to include
+ * it in fluidsynth's private header files (see comment in fluid_coreaudio.c)
  */
 
 #ifndef _FLUID_SYS_H
@@ -38,6 +41,124 @@
 
 #include "fluidsynth_priv.h"
 
+#if defined(__POWERPC__) && !(defined(__APPLE__) && defined(__MACH__))
+#include "config_maxmsp43.h"
+#endif
+
+#if HAVE_MATH_H
+#include <math.h>
+#endif
+
+#if HAVE_ERRNO_H
+#include <errno.h>
+#endif
+
+#if HAVE_STDARG_H
+#include <stdarg.h>
+#endif
+
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#if HAVE_FCNTL_H
+#include <fcntl.h>
+#endif
+
+#if HAVE_SYS_MMAN_H
+#include <sys/mman.h>
+#endif
+
+#if HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+
+#if HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+
+#if HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+
+#if HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+
+#if HAVE_NETINET_IN_H
+#include <netinet/in.h>
+#endif
+
+#if HAVE_NETINET_TCP_H
+#include <netinet/tcp.h>
+#endif
+
+#if HAVE_ARPA_INET_H
+#include <arpa/inet.h>
+#endif
+
+#if HAVE_LIMITS_H
+#include <limits.h>
+#endif
+
+#if HAVE_PTHREAD_H
+#include <pthread.h>
+#endif
+
+#if HAVE_OPENMP
+#include <omp.h>
+#endif
+
+#if HAVE_IO_H
+#include <io.h> // _open(), _close(), read(), write() on windows
+#endif
+
+#if HAVE_SIGNAL_H
+#include <signal.h>
+#endif
+
+/** Integer types  */
+#if HAVE_STDINT_H
+#include <stdint.h>
+
+#else
+
+/* Assume GLIB types */
+typedef gint8    int8_t;
+typedef guint8   uint8_t;
+typedef gint16   int16_t;
+typedef guint16  uint16_t;
+typedef gint32   int32_t;
+typedef guint32  uint32_t;
+typedef gint64   int64_t;
+typedef guint64  uint64_t;
+
+#endif
+
+#if defined(WIN32) &&  HAVE_WINDOWS_H
+#include <winsock2.h>
+#include <ws2tcpip.h>	/* Provides also socklen_t */
+
+/* WIN32 special defines */
+#define STDIN_FILENO 0
+#define STDOUT_FILENO 1
+#define STDERR_FILENO 2
+
+#ifdef _MSC_VER
+#pragma warning(disable : 4244)
+#pragma warning(disable : 4101)
+#pragma warning(disable : 4305)
+#pragma warning(disable : 4996)
+#endif
+
+#endif
+
+/* Darwin special defines (taken from config_macosx.h) */
+#ifdef DARWIN
+# define MACINTOSH
+# define __Types__
+#endif
+
 #ifdef LADSPA
 #include <gmodule.h>
 #endif
@@ -52,26 +173,12 @@
  */
 #define fluid_gerror_message(err)  ((err) ? err->message : "No error details")
 
-/* Misc */
-#if defined(__INTEL_COMPILER)
-#define FLUID_RESTRICT restrict
-#elif defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
-#define FLUID_RESTRICT __restrict__
-#elif defined(_MSC_VER) && _MSC_VER >= 1400
-#define FLUID_RESTRICT __restrict
-#else
-#warning "Dont know how this compiler handles restrict pointers, refuse to use them."
-#define FLUID_RESTRICT
-#endif
 
 #define FLUID_INLINE              inline
 #define FLUID_POINTER_TO_UINT     GPOINTER_TO_UINT
 #define FLUID_UINT_TO_POINTER     GUINT_TO_POINTER
 #define FLUID_POINTER_TO_INT      GPOINTER_TO_INT
 #define FLUID_INT_TO_POINTER      GINT_TO_POINTER
-#define FLUID_N_ELEMENTS(struct)  (sizeof (struct) / sizeof (struct[0]))
-#define FLUID_MEMBER_SIZE(struct, member)  ( sizeof (((struct *)0)->member) )
-
 #define FLUID_IS_BIG_ENDIAN       (G_BYTE_ORDER == G_BIG_ENDIAN)
 
 #define FLUID_LE32TOH(x)          GINT32_FROM_LE(x)
@@ -85,17 +192,6 @@
     (uint32_t)(((uint32_t)(_d) << 24) | ((uint32_t)(_c) << 16) | ((uint32_t)(_b) << 8) | (uint32_t)(_a)) 
 #endif
 
-
-#define fluid_return_if_fail(cond) \
-if(cond) \
-    ; \
-else \
-    return
-
-#define fluid_return_val_if_fail(cond, val) \
- fluid_return_if_fail(cond) (val)
-
-
 /*
  * Utility functions
  */
@@ -361,6 +457,12 @@ fluid_ostream_t fluid_get_stdout(void);
 int fluid_istream_readline(fluid_istream_t in, fluid_ostream_t out, char *prompt, char *buf, int len);
 int fluid_ostream_printf(fluid_ostream_t out, const char *format, ...);
 
+#if defined(WIN32)
+typedef SOCKET fluid_socket_t;
+#else
+typedef int fluid_socket_t;
+#endif
+
 /* The function should return 0 if no error occured, non-zero
    otherwise. If the function return non-zero, the socket will be
    closed by the server. */
diff --git a/src/utils/fluidsynth_priv.h b/src/utils/fluidsynth_priv.h
index 4df590e2..e299a5ff 100644
--- a/src/utils/fluidsynth_priv.h
+++ b/src/utils/fluidsynth_priv.h
@@ -18,6 +18,13 @@
  * 02110-1301, USA
  */
 
+/**
+ * @file fluidsynth_priv.h
+ * 
+ * lightweight part of fluid_sys.h, containing forward declarations of fluidsynth's private types and private macros
+ *
+ * include this one file in fluidsynth's private header files
+ */
 
 #ifndef _FLUIDSYNTH_PRIV_H
 #define _FLUIDSYNTH_PRIV_H
@@ -26,136 +33,18 @@
 
 #include "config.h"
 
-#if defined(__POWERPC__) && !(defined(__APPLE__) && defined(__MACH__))
-#include "config_maxmsp43.h"
+#if HAVE_STDLIB_H
+#include <stdlib.h> // malloc, free
+#endif
+
+#if HAVE_STDIO_H
+#include <stdio.h> // printf
 #endif
 
 #if HAVE_STRING_H
 #include <string.h>
 #endif
 
-#if HAVE_STDLIB_H
-#include <stdlib.h>
-#endif
-
-#if HAVE_STDIO_H
-#include <stdio.h>
-#endif
-
-#if HAVE_MATH_H
-#include <math.h>
-#endif
-
-#if HAVE_ERRNO_H
-#include <errno.h>
-#endif
-
-#if HAVE_STDARG_H
-#include <stdarg.h>
-#endif
-
-#if HAVE_UNISTD_H
-#include <unistd.h>
-#endif
-
-#if HAVE_FCNTL_H
-#include <fcntl.h>
-#endif
-
-#if HAVE_SYS_MMAN_H
-#include <sys/mman.h>
-#endif
-
-#if HAVE_SYS_TYPES_H
-#include <sys/types.h>
-#endif
-
-#if HAVE_SYS_STAT_H
-#include <sys/stat.h>
-#endif
-
-#if HAVE_SYS_TIME_H
-#include <sys/time.h>
-#endif
-
-#if HAVE_SYS_SOCKET_H
-#include <sys/socket.h>
-#endif
-
-#if HAVE_NETINET_IN_H
-#include <netinet/in.h>
-#endif
-
-#if HAVE_NETINET_TCP_H
-#include <netinet/tcp.h>
-#endif
-
-#if HAVE_ARPA_INET_H
-#include <arpa/inet.h>
-#endif
-
-#if HAVE_LIMITS_H
-#include <limits.h>
-#endif
-
-#if HAVE_PTHREAD_H
-#include <pthread.h>
-#endif
-
-#if HAVE_OPENMP
-#include <omp.h>
-#endif
-
-#if HAVE_IO_H
-#include <io.h> // _open(), _close(), read(), write() on windows
-#endif
-
-#if HAVE_SIGNAL_H
-#include <signal.h>
-#endif
-
-/** Integer types  */
-#if HAVE_STDINT_H
-#include <stdint.h>
-
-#else
-
-/* Assume GLIB types */
-typedef gint8    int8_t;
-typedef guint8   uint8_t;
-typedef gint16   int16_t;
-typedef guint16  uint16_t;
-typedef gint32   int32_t;
-typedef guint32  uint32_t;
-typedef gint64   int64_t;
-typedef guint64  uint64_t;
-
-#endif
-
-#if defined(WIN32) &&  HAVE_WINDOWS_H
-#include <winsock2.h>
-#include <ws2tcpip.h>	/* Provides also socklen_t */
-
-/* WIN32 special defines */
-#define STDIN_FILENO 0
-#define STDOUT_FILENO 1
-#define STDERR_FILENO 2
-
-#ifdef _MSC_VER
-#pragma warning(disable : 4244)
-#pragma warning(disable : 4101)
-#pragma warning(disable : 4305)
-#pragma warning(disable : 4996)
-#endif
-
-#endif
-
-/* Darwin special defines (taken from config_macosx.h) */
-#ifdef DARWIN
-# define MACINTOSH
-# define __Types__
-#endif
-
 
 #include "fluidsynth.h"
 
@@ -171,13 +60,6 @@ typedef float fluid_real_t;
 typedef double fluid_real_t;
 #endif
 
-
-#if defined(WIN32)
-typedef SOCKET fluid_socket_t;
-#else
-typedef int fluid_socket_t;
-#endif
-
 #if defined(SUPPORTS_VLA)
 #  define FLUID_DECLARE_VLA(_type, _name, _len) \
      _type _name[_len]
@@ -243,7 +125,6 @@ typedef void (*fluid_rvoice_function_t)(void *obj, const fluid_rvoice_param_t pa
  *
  *                      SYSTEM INTERFACE
  */
-typedef FILE  *fluid_file;
 
 #define FLUID_MALLOC(_n)             malloc(_n)
 #define FLUID_REALLOC(_p,_n)         realloc(_p,_n)
@@ -354,4 +235,30 @@ do { strncpy(_dst,_src,_n); \
 
 char *fluid_error(void);
 
+/* Misc */
+#if defined(__INTEL_COMPILER)
+#define FLUID_RESTRICT restrict
+#elif defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
+#define FLUID_RESTRICT __restrict__
+#elif defined(_MSC_VER) && _MSC_VER >= 1400
+#define FLUID_RESTRICT __restrict
+#else
+#warning "Dont know how this compiler handles restrict pointers, refuse to use them."
+#define FLUID_RESTRICT
+#endif
+
+#define FLUID_N_ELEMENTS(struct)  (sizeof (struct) / sizeof (struct[0]))
+#define FLUID_MEMBER_SIZE(struct, member)  ( sizeof (((struct *)0)->member) )
+
+
+#define fluid_return_if_fail(cond) \
+if(cond) \
+    ; \
+else \
+    return
+
+#define fluid_return_val_if_fail(cond, val) \
+ fluid_return_if_fail(cond) (val)
+
+
 #endif /* _FLUIDSYNTH_PRIV_H */
diff --git a/test/test_preset_sample_loading.c b/test/test_preset_sample_loading.c
index fcccc639..5f884cf1 100644
--- a/test/test_preset_sample_loading.c
+++ b/test/test_preset_sample_loading.c
@@ -2,7 +2,7 @@
 #include "fluidsynth.h"
 #include "sfloader/fluid_sfont.h"
 #include "sfloader/fluid_defsfont.h"
-#include "utils/fluidsynth_priv.h"
+#include "utils/fluid_sys.h"
 #include "utils/fluid_list.h"
 
 // load our sf2 and sf3 test soundfonts, with and without dynamic sample loading
diff --git a/test/test_sample_cache.c b/test/test_sample_cache.c
index 16771649..a76d2508 100644
--- a/test/test_sample_cache.c
+++ b/test/test_sample_cache.c
@@ -1,7 +1,7 @@
 
 #include "test.h"
 #include "fluidsynth.h" // use local fluidsynth header
-#include "utils/fluidsynth_priv.h"
+#include "utils/fluid_sys.h"
 
 
 // this test aims to make sure that sample data used by multiple synths is not freed
diff --git a/test/test_sample_rate_change.c b/test/test_sample_rate_change.c
index 48e66df8..d0a5d643 100644
--- a/test/test_sample_rate_change.c
+++ b/test/test_sample_rate_change.c
@@ -4,7 +4,7 @@
 #include "synth/fluid_synth.h"
 #include "synth/fluid_voice.h"
 #include "rvoice/fluid_rvoice.h"
-#include "utils/fluidsynth_priv.h"
+#include "utils/fluid_sys.h"
 
 static void verify_sample_rate(fluid_synth_t *synth, int expected_srate)
 {
diff --git a/test/test_sf3_sfont_loading.c b/test/test_sf3_sfont_loading.c
index d454a1e4..ed6064e5 100644
--- a/test/test_sf3_sfont_loading.c
+++ b/test/test_sf3_sfont_loading.c
@@ -1,7 +1,7 @@
 #include "test.h"
 #include "fluidsynth.h"
 #include "sfloader/fluid_sfont.h"
-#include "utils/fluidsynth_priv.h"
+#include "utils/fluid_sys.h"
 
 
 int main(void)
diff --git a/test/test_sfont_loading.c b/test/test_sfont_loading.c
index 9cac3d07..c8f4c043 100644
--- a/test/test_sfont_loading.c
+++ b/test/test_sfont_loading.c
@@ -2,7 +2,7 @@
 #include "test.h"
 #include "fluidsynth.h"
 #include "sfloader/fluid_sfont.h"
-#include "utils/fluidsynth_priv.h"
+#include "utils/fluid_sys.h"
 
 
 // this tests the soundfont loading API of the synth.
diff --git a/test/test_snprintf.c b/test/test_snprintf.c
index d0fee749..35722e5a 100644
--- a/test/test_snprintf.c
+++ b/test/test_snprintf.c
@@ -1,6 +1,6 @@
 
 #include "test.h"
-#include "utils/fluidsynth_priv.h"
+#include "utils/fluid_sys.h"
 
 // this test makes sure FLUID_SNPRINTF uses a proper C99 compliant implementation