A workaround to allow compilation of recent versions of MAME with gcc on PowerPC, including ppc64 and ppc64le.

mame_gcc_workaround.diff

diff --git a/3rdparty/bx/include/bx/platform.h b/3rdparty/bx/include/bx/platform.h
index e0031ec2c38..5cb5f65e3ad 100644
--- a/3rdparty/bx/include/bx/platform.h
+++ b/3rdparty/bx/include/bx/platform.h
@@ -133,8 +133,14 @@
 #endif //
 
 #if BX_CPU_PPC
-#	undef  BX_CPU_ENDIAN_BIG
-#	define BX_CPU_ENDIAN_BIG 1
+// _LITTLE_ENDIAN exists on ppc64le.
+#	if _LITTLE_ENDIAN
+#		undef  BX_CPU_ENDIAN_LITTLE
+#		define BX_CPU_ENDIAN_LITTLE 1
+#	else
+#		undef  BX_CPU_ENDIAN_BIG
+#		define BX_CPU_ENDIAN_BIG 1
+#	endif
 #else
 #	undef  BX_CPU_ENDIAN_LITTLE
 #	define BX_CPU_ENDIAN_LITTLE 1
diff --git a/makefile b/makefile
index 11b5a3a27b1..059a5192df0 100644
--- a/makefile
+++ b/makefile
@@ -394,6 +394,12 @@ BIGENDIAN := 1
 endif
 endif # BIGENDIAN
 
+# Work around an issue with long doubles on ppc64 (#3157)
+ifneq (,$(findstring ppc64,$(UNAME)))
+ARCHOPTS_C += -mlong-double-64
+ARCHOPTS_CXX += -mlong-double-64
+endif
+
 ifndef PYTHON_EXECUTABLE
 PYTHON := python
 else