add fwkren as a replacement for powershell exec

MAKE.bat

@@ -472,7 +472,8 @@ if "%1"=="fwk" (
         set "filename=%%~nxf"
         if /i not "!filename:~0,4!"=="3rd_" (
             echo Processing: %%f
-            powershell -command "(Get-Content '%%f') -creplace 'v4k', 'fwk' -creplace 'V4K', 'FWK' | Set-Content '%%f'"
+            rem powershell -command "(Get-Content '%%f') -creplace 'v4k', 'fwk' -creplace 'V4K', 'FWK' | Set-Content '%%f'"
+            tools\fwkren.exe %%f from
         ) else (
             echo Skipping %%f
         )
@@ -495,7 +496,8 @@ if "%1"=="back" (
         set "filename=%%~nxf"
         if /i not "!filename:~0,4!"=="3rd_" (
             echo Processing: %%f
-            powershell -command "(Get-Content '%%f') -creplace 'fwk', 'v4k' -creplace 'FWK', 'V4K' | Set-Content '%%f'"
+            rem powershell -command "(Get-Content '%%f') -creplace 'fwk', 'v4k' -creplace 'FWK', 'V4K' | Set-Content '%%f'"
+            tools\fwkren.exe %%f to
         ) else (
             echo Skipping %%f
         )

tools/fwkren.c

@@ -0,0 +1,30 @@
+#include "v4k.h"
+
+int main(int argc, char **argv) {
+	if (argc != 3) {
+		fprintf(stderr, "usage: %s [file] [mode]\n", argv[0]);
+		fprintf(stderr, "file: %s\n", "source file to process");
+		fprintf(stderr, "mode: %s\n", "to|from");
+		return 1;
+	}
+
+	char *buf = file_read(argv[1]);
+	if (!buf) {
+		fprintf(stderr, "error: %s\n", "file does not exist!");
+		return 2;
+	}
+
+	char mode = !strcmp(argv[2], "from");
+
+	if (!mode) {
+		buf = strswap(buf, "v4k", "fwk");
+		buf = strswap(buf, "V4K", "FWK");
+	} else {
+		buf = strswap(buf, "fwk", "v4k");
+		buf = strswap(buf, "FWK", "V4K");
+	}
+
+	file_write(argv[1], buf, strlen(buf));
+
+	return 0;	
+}