diff --git a/mingw-w64-crt/Makefile.am b/mingw-w64-crt/Makefile.am
index 990e883..4e3dfc9 100644
--- a/mingw-w64-crt/Makefile.am
+++ b/mingw-w64-crt/Makefile.am
@@ -1244,6 +1244,15 @@
 %.def: %.def.in
 	$(MKDIR_P) $(@D) && $(CPP) -x c $< -Wp,-w -undef -P -I$(top_srcdir)/def-include > $@
 
+lib32/%.def: lib-common/%.def.in
+	$(MKDIR_P) $(@D) && $(CPP) -x c $< -Wp,-w -undef -P -I$(top_srcdir)/def-include -DDEF_I386 > $@
+
+lib64/%.def: lib-common/%.def.in
+	$(MKDIR_P) $(@D) && $(CPP) -x c $< -Wp,-w -undef -P -I$(top_srcdir)/def-include -DDEF_X64 > $@
+
+libarm32/%.def: lib-common/%.def.in
+	$(MKDIR_P) $(@D) && $(CPP) -x c $< -Wp,-w -undef -P -I$(top_srcdir)/def-include -DDEF_ARM32 > $@
+
 # Don't compile these, but install as is:
 #
 libsrcdir=$(includedir)
@@ -1277,6 +1286,7 @@
   $(top_srcdir)/lib32/*.mri \
   $(top_srcdir)/lib64/*.mri \
   $(top_srcdir)/libarm32/*.mri \
+  $(top_srcdir)/lib-common/*.def.in \
   $(top_srcdir)/lib32/*.def.in \
   $(top_srcdir)/lib64/*.def.in \
   $(top_srcdir)/libarm32/*.def.in \
diff --git a/mingw-w64-crt/Makefile.in b/mingw-w64-crt/Makefile.in
index 2e69775..590f23f 100644
--- a/mingw-w64-crt/Makefile.in
+++ b/mingw-w64-crt/Makefile.in
@@ -6980,8 +6980,9 @@
 	$(top_srcdir)/lib-common/*.def $(top_srcdir)/lib32/*.def \
 	$(top_srcdir)/lib64/*.def $(top_srcdir)/libarm32/*.def \
 	$(top_srcdir)/lib32/*.mri $(top_srcdir)/lib64/*.mri \
-	$(top_srcdir)/libarm32/*.mri $(top_srcdir)/lib32/*.def.in \
-	$(top_srcdir)/lib64/*.def.in $(top_srcdir)/libarm32/*.def.in \
+	$(top_srcdir)/libarm32/*.mri $(top_srcdir)/lib-common/*.def.in \
+	$(top_srcdir)/lib32/*.def.in $(top_srcdir)/lib64/*.def.in \
+	$(top_srcdir)/libarm32/*.def.in \
 	$(top_srcdir)/def-include/*.def.in crt/binmode.c \
 	crt/crtbegin.c crt/crtdll.c crt/crtend.c crt/crtexe.c \
 	crt/CRT_fp8.c crt/CRT_fp10.c crt/CRT_glob.c crt/CRT_noglob.c \
@@ -49240,6 +49241,15 @@
 %.def: %.def.in
 	$(MKDIR_P) $(@D) && $(CPP) -x c $< -Wp,-w -undef -P -I$(top_srcdir)/def-include > $@
 
+lib32/%.def: lib-common/%.def.in
+	$(MKDIR_P) $(@D) && $(CPP) -x c $< -Wp,-w -undef -P -I$(top_srcdir)/def-include -DDEF_I386 > $@
+
+lib64/%.def: lib-common/%.def.in
+	$(MKDIR_P) $(@D) && $(CPP) -x c $< -Wp,-w -undef -P -I$(top_srcdir)/def-include -DDEF_X64 > $@
+
+libarm32/%.def: lib-common/%.def.in
+	$(MKDIR_P) $(@D) && $(CPP) -x c $< -Wp,-w -undef -P -I$(top_srcdir)/def-include -DDEF_ARM32 > $@
+
 dist-hook:
 	find $(top_distdir) -name ".svn" -delete
 
diff --git a/mingw-w64-crt/def-include/func.def.in b/mingw-w64-crt/def-include/func.def.in
new file mode 100644
index 0000000..382cfd3
--- /dev/null
+++ b/mingw-w64-crt/def-include/func.def.in
@@ -0,0 +1,42 @@
+// F64         - function available on all 64 bit architectures
+// F_X86_ANY   - function available on i386 and x86_64
+// F_I386      - function available only on i386
+// F_X64       - function available only on x86_64
+// F_ARM32     - function available only on arm32
+// F_ARM_ANY   - function available on 32 and 64 bit arm
+// F_NON_I386  - function available on everything but i386
+#if defined(DEF_X64)
+#define F64(x) x
+#define F_X64(x) x
+#define F_X86_ANY(x) x
+#define F_NON_I386(x) x
+#elif defined(DEF_I386)
+#define F_I386(x) x
+#define F_X86_ANY(x) x
+#elif defined(DEF_ARM32)
+#define F_ARM32(x) x
+#define F_ARM_ANY(x) x
+#define F_NON_I386(x) x
+#endif
+
+#ifndef F64
+#define F64(x)
+#endif
+#ifndef F_X86_ANY
+#define F_X86_ANY(x)
+#endif
+#ifndef F_I386
+#define F_I386(x)
+#endif
+#ifndef F_X64
+#define F_X64(x)
+#endif
+#ifndef F_ARM_ANY
+#define F_ARM_ANY(x)
+#endif
+#ifndef F_ARM32
+#define F_ARM32(x)
+#endif
+#ifndef F_NON_I386
+#define F_NON_I386(x)
+#endif