compat/nedmalloc: Fix some sparse warnings

Sparse issues many "Using plain integer as NULL pointer" warnings
while checking nedmalloc.c (at least 98 such warnings before giving
up due to "too many warnings"). In addition, sparse issues some
"non-ANSI function declaration" type warnings for the symbols
'win32_getcurrentthreadid', 'malloc_stats' and 'malloc_footprint'.

In order to suppress the NULL pointer warnings, rather than replace
all uses of '0' as a null pointer representation with NULL, we add
-Wno-non-pointer-null to SPARSE_FLAGS while checking nedmalloc.c.

In order to suppress the "non-ANSI function declaration" warnings,
we simply include the missing 'empty parameter list' prototype (void)
in the function declarations.
Signed-off-by: NRamsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Makefile

@@ -2004,6 +2004,7 @@ endif
 ifdef USE_NED_ALLOCATOR
 compat/nedmalloc/nedmalloc.sp compat/nedmalloc/nedmalloc.o: EXTRA_CPPFLAGS = \
 	-DNDEBUG -DOVERRIDE_STRDUP -DREPLACE_SYSTEM_ALLOCATOR
+compat/nedmalloc/nedmalloc.sp: SPARSE_FLAGS += -Wno-non-pointer-null
 endif
 
 git-%$X: %.o GIT-LDFLAGS $(GITLIBS)

compat/nedmalloc/malloc.c.h

@@ -1802,7 +1802,7 @@ struct win32_mlock_t
 
 static MLOCK_T malloc_global_mutex = { 0, 0, 0};
 
-static FORCEINLINE long win32_getcurrentthreadid() {
+static FORCEINLINE long win32_getcurrentthreadid(void) {
 #ifdef _MSC_VER
 #if defined(_M_IX86)
   long *threadstruct=(long *)__readfsdword(0x18);

compat/nedmalloc/nedmalloc.c

@@ -159,8 +159,8 @@ struct mallinfo nedmallinfo(void) THROWSPEC			{ return nedpmallinfo(0); }
 #endif
 int    nedmallopt(int parno, int value) THROWSPEC	{ return nedpmallopt(0, parno, value); }
 int    nedmalloc_trim(size_t pad) THROWSPEC			{ return nedpmalloc_trim(0, pad); }
-void   nedmalloc_stats() THROWSPEC					{ nedpmalloc_stats(0); }
-size_t nedmalloc_footprint() THROWSPEC				{ return nedpmalloc_footprint(0); }
+void   nedmalloc_stats(void) THROWSPEC					{ nedpmalloc_stats(0); }
+size_t nedmalloc_footprint(void) THROWSPEC				{ return nedpmalloc_footprint(0); }
 void **nedindependent_calloc(size_t elemsno, size_t elemsize, void **chunks) THROWSPEC	{ return nedpindependent_calloc(0, elemsno, elemsize, chunks); }
 void **nedindependent_comalloc(size_t elems, size_t *sizes, void **chunks) THROWSPEC	{ return nedpindependent_comalloc(0, elems, sizes, chunks); }