Enabled position independent executable for generic GCC/Clang

This affects mostly Linux (and probably MinGW) as default toolchains for Windows and macOS have the corresponding option turned on by default

CMakeLists.txt

@@ -234,6 +234,12 @@ else()
 	if( APPLE AND "${CMAKE_C_COMPILER_ID}" STREQUAL "GNU" )
 		set( ALL_C_FLAGS "-static-libgcc" )
 	endif()
+
+	if( NOT APPLE )
+		# Generic GCC/Clang requires position independent executable to be enabled explicitly
+		set( ALL_C_FLAGS "${ALL_C_FLAGS} -fPIE" )
+		set( CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -pie" )
+	endif()
 endif()
 
 set( CMAKE_EXE_LINKER_FLAGS_RELEASE "${CMAKE_EXE_LINKER_FLAGS_RELEASE} ${REL_LINKER_FLAGS}" )

src/m_fixed.h

@@ -7,7 +7,7 @@
 // Unfortunately, the Scale function still gets badly handled on 32 bit x86 platforms so it's the last remaining piece of inline assembly 
 
 // GCC inlines
-#if defined(__GNUC__) && defined(__i386__) && !defined(__clang__)
+#if defined(__GNUC__) && defined(__i386__) && !defined(__clang__) && !defined(__PIC__)
 #ifndef alloca
 // MinGW does not seem to come with alloca defined.
 #define alloca __builtin_alloca