Tweaks to compile the release build with clang. Now if it only would not

generate curious code like this one (Ubuntu 11.10's clang 2.9 on i386):

   0x080a57ea <+538>:   xor    %al,%al
   0x080a57ec <+540>:   test   %al,%al
   0x080a57ee <+542>:   jnz    0x80a57f2 <initgroupfile+546>
=> 0x080a57f0 <+544>:   jmp    0x80a57f0 <initgroupfile+544>
   0x080a57f2 <+546>:   shl    $0x4,%edi

git-svn-id: https://svn.eduke32.com/eduke32@2182 1a8010ca-5511-0410-912e-c29ae57300e0

polymer/eduke32/Makefile.common

@@ -78,7 +78,10 @@ endif
 
 ifneq (0,$(RELEASE))
     # Debugging disabled
-    debug=-funswitch-loops -O$(OPTLEVEL)
+    debug=-O$(OPTLEVEL)
+    ifneq ($(CC),clang)
+        debug=-funswitch-loops
+    endif
     ifeq (0,$(DEBUGANYWAY))
         debug+= -fomit-frame-pointer
     endif

polymer/eduke32/build/src/engine.c

@@ -1806,6 +1806,13 @@ int32_t checksectorpointer(int16_t i, int16_t sectnum)
 
 #undef WALLS_ARE_CONSISTENT
 
+#ifdef __clang__
+int32_t engine_dummy_function_to_keep_symbols(void)
+{
+    return shlookup[0] | sqrtable[0];
+}
+#endif
+
 
 #if defined(_MSC_VER) && !defined(NOASM)
 

polymer/eduke32/build/src/kplib.c

@@ -188,6 +188,13 @@ static int32_t gotcmov = -2, abstab10[1024] ASMNAME("abstab10");
 static int32_t qhufval0[1<<LOGQHUFSIZ0], qhufval1[1<<LOGQHUFSIZ1];
 static uint8_t qhufbit0[1<<LOGQHUFSIZ0], qhufbit1[1<<LOGQHUFSIZ1];
 
+#ifdef __clang__
+int32_t kplib_dummy_function_to_keep_symbols(void)
+{
+    return abstab10[0] | trnsrgb;
+}
+#endif
+
 #if defined(_MSC_VER) && !defined(NOASM)
 
 static _inline uint32_t bswap(uint32_t a)