diff --git a/Makefile b/Makefile
index 38ab41c..3abf9f9 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@
 
 TARGET    = ddraw.dll
 LDFLAGS   = -Wl,--enable-stdcall-fixup -s -static -shared
-CFLAGS    = -Iinc -O2 -march=i486 -Wall
+CFLAGS    = -Iinc -O2 -march=i486 -Wall -std=c99
 LIBS      = -lgdi32 -lwinmm -ldbghelp -lole32
 
 COMMIT   := $(shell git describe --match=NeVeRmAtCh --always --dirty || echo UNKNOWN)
@@ -10,13 +10,20 @@ BRANCH   := $(shell git rev-parse --abbrev-ref HEAD || echo UNKNOWN)
 
 CMDTEST  := $(shell echo \"\")
 ifeq ($(CMDTEST),\"\")
-# Windows
-ECOMMIT  := $(shell echo #define GIT_COMMIT "$(COMMIT)" > inc/git.h)
-EBRANCH  := $(shell echo #define GIT_BRANCH "$(BRANCH)" >> inc/git.h)
+	# Windows
+	CMDTEST  := $(shell echo "\#")
+	ifeq ($(CMDTEST),"\#")
+    	# gmake
+		ECOMMIT  := $(shell echo \#define GIT_COMMIT "$(COMMIT)" > inc/git.h)
+		EBRANCH  := $(shell echo \#define GIT_BRANCH "$(BRANCH)" >> inc/git.h)
+    else
+		ECOMMIT  := $(shell echo #define GIT_COMMIT "$(COMMIT)" > inc/git.h)
+		EBRANCH  := $(shell echo #define GIT_BRANCH "$(BRANCH)" >> inc/git.h)
+	endif
 else
-# Either *nix or Windows with sh.exe (e.g. w64devkit)
-ECOMMIT  := $(shell echo \#define GIT_COMMIT \"$(COMMIT)\" > inc/git.h)
-EBRANCH  := $(shell echo \#define GIT_BRANCH \"$(BRANCH)\" >> inc/git.h)
+	# Either *nix or Windows with BusyBox (e.g. w64devkit)
+	ECOMMIT  := $(shell echo \#define GIT_COMMIT \"$(COMMIT)\" > inc/git.h)
+	EBRANCH  := $(shell echo \#define GIT_BRANCH \"$(BRANCH)\" >> inc/git.h)
 endif
 
 CC        = i686-w64-mingw32-gcc
diff --git a/inc/debug.h b/inc/debug.h
index 6ac7f7b..be19a05 100644
--- a/inc/debug.h
+++ b/inc/debug.h
@@ -28,13 +28,7 @@ void dbg_dump_dds_blt_fast_flags(DWORD flags);
 void dbg_dump_dds_lock_flags(DWORD flags);
 char* dbg_d3d9_hr_to_str(HRESULT hr);
 char* dbg_mes_to_str(int id);
-
-void __cdecl dbg_invoke_watson(
-    _In_opt_z_ wchar_t const*,
-    _In_opt_z_ wchar_t const*,
-    _In_opt_z_ wchar_t const*,
-    _In_       unsigned int,
-    _In_       uintptr_t);
+void __cdecl dbg_invoke_watson(wchar_t const*, wchar_t const*, wchar_t const*, unsigned int, uintptr_t);
 
 extern double g_dbg_frame_time;
 extern DWORD g_dbg_frame_count;