win32: allow building with pedantic mode enabled

In preparation to building with pedantic mode enabled, change a couple
of places where the current mingw gcc compiler provided with the SDK
reports issues.

A full fix for the incompatible use of (void *) to store function
pointers has been punted, with the minimal change to instead use a
generic function pointer (FARPROC), and therefore the (hopefully)
temporary need to disable incompatible pointer warnings.

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

compat/nedmalloc/nedmalloc.c

@@ -510,7 +510,7 @@ static void threadcache_free(nedpool *p, threadcache *tc, int mymspace, void *me
 	assert(idx<=THREADCACHEMAXBINS);
 	if(tck==*binsptr)
 	{
-		fprintf(stderr, "Attempt to free already freed memory block %p - aborting!\n", tck);
+		fprintf(stderr, "Attempt to free already freed memory block %p - aborting!\n", (void *)tck);
 		abort();
 	}
 #ifdef FULLSANITYCHECKS

compat/win32/lazyload.h

@@ -37,7 +37,7 @@ struct proc_addr {
 #define INIT_PROC_ADDR(function) \
 	(function = get_proc_addr(&proc_addr_##function))
 
-static inline void *get_proc_addr(struct proc_addr *proc)
+static inline FARPROC get_proc_addr(struct proc_addr *proc)
 {
 	/* only do this once */
 	if (!proc->initialized) {

config.mak.dev

@@ -1,11 +1,18 @@
+ifndef COMPILER_FEATURES
+COMPILER_FEATURES := $(shell ./detect-compiler $(CC))
+endif
+
 ifeq ($(filter no-error,$(DEVOPTS)),)
 DEVELOPER_CFLAGS += -Werror
 SPARSE_FLAGS += -Wsparse-error
 endif
+DEVELOPER_CFLAGS += -Wall
 ifneq ($(filter pedantic,$(DEVOPTS)),)
 DEVELOPER_CFLAGS += -pedantic
+ifneq ($(filter gcc5,$(COMPILER_FEATURES)),)
+DEVELOPER_CFLAGS += -Wno-incompatible-pointer-types
+endif
 endif
-DEVELOPER_CFLAGS += -Wall
 DEVELOPER_CFLAGS += -Wdeclaration-after-statement
 DEVELOPER_CFLAGS += -Wformat-security
 DEVELOPER_CFLAGS += -Wold-style-definition
@@ -16,10 +23,6 @@ DEVELOPER_CFLAGS += -Wunused
 DEVELOPER_CFLAGS += -Wvla
 DEVELOPER_CFLAGS += -fno-common
 
-ifndef COMPILER_FEATURES
-COMPILER_FEATURES := $(shell ./detect-compiler $(CC))
-endif
-
 ifneq ($(filter clang4,$(COMPILER_FEATURES)),)
 DEVELOPER_CFLAGS += -Wtautological-constant-out-of-range-compare
 endif