Windows build fixes.

Author: GJDuck

llvm-4.0.0.src/projects/compiler-rt/lib/lowfat/lowfat.c

@@ -55,7 +55,9 @@ static LOWFAT_NOINLINE void lowfat_warning(const char *format, ...);
 static LOWFAT_DATA uint8_t *lowfat_seed = NULL;
 static LOWFAT_DATA size_t lowfat_seed_pos = LOWFAT_PAGE_SIZE;
 static LOWFAT_DATA bool lowfat_malloc_inited = false;
+#ifndef LOWFAT_WINDOWS
 static LOWFAT_DATA char **lowfat_envp = NULL;
+#endif
 
 #ifdef LOWFAT_WINDOWS
 #include "lowfat_windows.c"

llvm-4.0.0.src/projects/compiler-rt/lib/lowfat/lowfat_malloc.c

@@ -63,8 +63,13 @@ static void *lowfat_fallback_malloc(size_t size)
 #endif      /* LOWFAT_NO_STD_MALLOC_FALLBACK */
 }
 
+#ifndef LOWFAT_WINDOWS
 #define lowfat_fallback_free(x)         __libc_free(x)
 #define lowfat_fallback_realloc(x, y)   __libc_realloc((x), (y))
+#else
+#define lowfat_fallback_free(x)         free(x)
+#define lowfat_fallback_realloc(x, y)   realloc((x), (y))
+#endif
 
 /*
  * Initialize the lowfat_malloc() state.