diff --git a/polymer/eduke32/build/include/compat.h b/polymer/eduke32/build/include/compat.h
index 189da6cc5..d7128be00 100644
--- a/polymer/eduke32/build/include/compat.h
+++ b/polymer/eduke32/build/include/compat.h
@@ -21,6 +21,27 @@
 #endif
 #endif
 
+#ifdef __GNUC__
+# define EDUKE32_GCC_PREREQ(major, minor) (major > __GNUC__ || (major == __GNUC__ && minor >= __GNUC_MINOR__))
+#else
+# define EDUKE32_GCC_PREREQ(major, minor) 0
+#endif
+
+#ifdef __clang__
+# define EDUKE32_CLANG_PREREQ(major, minor) (major > __clang_major__ || (major == __clang_major__ && minor >= __clang_minor__))
+#else
+# define EDUKE32_CLANG_PREREQ(major, minor) 0
+#endif
+#ifndef __has_builtin
+# define __has_builtin(x) 0  // Compatibility with non-clang compilers.
+#endif
+#ifndef __has_feature
+# define __has_feature(x) 0  // Compatibility with non-clang compilers.
+#endif
+#ifndef __has_extension
+# define __has_extension __has_feature // Compatibility with pre-3.0 compilers.
+#endif
+
 #ifndef UNREFERENCED_PARAMETER
     #define UNREFERENCED_PARAMETER(x) x=x
 #endif
@@ -37,17 +58,19 @@
 # define ATTRIBUTE_OPTIMIZE(str)
 #endif
 
-#if defined __GNUC__ || defined __clang__
+#if defined __GNUC__ || __has_builtin(__builtin_expect)
 #define EDUKE32_PREDICT_TRUE(x)       __builtin_expect(!!(x),1)
 #define EDUKE32_PREDICT_FALSE(x)     __builtin_expect(!!(x),0)
+#else
+#define EDUKE32_PREDICT_TRUE(x) (x)
+#define EDUKE32_PREDICT_FALSE(x) (x)
+#endif
+
+#if EDUKE32_GCC_PREREQ(4,5)  || __has_builtin(__builtin_unreachable)
 #define EDUKE32_UNREACHABLE_SECTION(...)   __builtin_unreachable()
 #elif _MSC_VER
-#define EDUKE32_PREDICT_TRUE(x) (x)
-#define EDUKE32_PREDICT_FALSE(x) (x)
 #define EDUKE32_UNREACHABLE_SECTION(...)   __assume(0)
-#else 
-#define EDUKE32_PREDICT_TRUE(x) (x)
-#define EDUKE32_PREDICT_FALSE(x) (x)
+#else
 #define EDUKE32_UNREACHABLE_SECTION(...) __VA_ARGS__
 #endif
 
@@ -377,6 +400,7 @@ static inline int32_t Blrintf(const float x)
     return n;
 }
 #else
+#include <math.h>
 #define Blrintf lrintf
 #endif
 
diff --git a/polymer/eduke32/build/src/a-c.c b/polymer/eduke32/build/src/a-c.c
index eceb6b120..a87fcb782 100644
--- a/polymer/eduke32/build/src/a-c.c
+++ b/polymer/eduke32/build/src/a-c.c
@@ -191,14 +191,8 @@ extern uint32_t vplce[4];
 extern int32_t vince[4];
 extern intptr_t bufplce[4];
 
-#if !defined __has_extension
-# define __has_extension(x) 0
-#endif
-
-#if (defined __GNUC__ && __GNUC_MINOR__ >= 7) || (defined __clang__ && __has_extension(attribute_ext_vector_type))
-# if defined _WIN64 || defined __amd64 || defined __x86_64 || defined __x86_64__
-#  define USE_VECTOR_EXT
-# endif
+#if (EDUKE32_GCC_PREREQ(4,7) || __has_extension(attribute_ext_vector_type)) && defined BITNESS64
+# define USE_VECTOR_EXT
 #endif
 
 #ifdef USE_VECTOR_EXT
diff --git a/polymer/eduke32/build/src/kplib.c b/polymer/eduke32/build/src/kplib.c
index 073a565a6..f46552d17 100644
--- a/polymer/eduke32/build/src/kplib.c
+++ b/polymer/eduke32/build/src/kplib.c
@@ -87,7 +87,7 @@ static __inline int32_t _lrotl(int32_t i, int sh)
 #define min(a,b) (((a) < (b)) ? (a) : (b))
 #endif
 
-#if defined __clang__ && __clang_major__==3
+#if defined __clang__ && __clang_major__==3 && __clang_minor__==1
 // clang 3.1 SVN r149129, assertion failure with inline asm
 # define NOASM 1
 #endif
diff --git a/polymer/eduke32/build/src/winbits.c b/polymer/eduke32/build/src/winbits.c
index 8952eff07..38c709933 100644
--- a/polymer/eduke32/build/src/winbits.c
+++ b/polymer/eduke32/build/src/winbits.c
@@ -10,7 +10,7 @@
 
 #include "winbits.h"
 
-#if defined(_M_X64) || defined(__amd64__) || defined(__x86_64__)
+#ifdef BITNESS64
 # define EBACKTRACEDLL "ebacktrace1-64.dll"
 #else
 # define EBACKTRACEDLL "ebacktrace1.dll"
@@ -291,6 +291,6 @@ int32_t addsearchpath_ProgramFiles(const char *p)
 
 
 // Workaround for a bug in mingwrt-4.0.0 and up where a function named main() in misc/src/libcrt/gdtoa/qnan.c takes precedence over the proper one in src/libcrt/crt/main.c.
-#if (defined __MINGW32__ && __GNUC__ == 4 && __GNUC_MINOR__  >= 8) || (defined __clang__ && __clang_major__ == 3 && __clang_minor__ >= 4)
+#if (defined __MINGW32__ && EDUKE32_GCC_PREREQ(4,8)) || EDUKE32_CLANG_PREREQ(3,4)
 # include "mingw_main.c"
 #endif