dirname: fix visual studio version

hackish way to keep same function behavior as mingw/linux
the string result can't be freed on linux...

Not thread safe, but we dont care for our usage...

compat.h

@@ -48,15 +48,19 @@ static __inline int setpriority(int which, int who, int prio)
 typedef int ssize_t;
 
 #include <stdlib.h>
+// This static var is made to be compatible with linux/mingw (no free on string result)
+// This is not thread safe but we only use that once on process start
+static char dirname_buffer[_MAX_PATH] = { 0 };
 static __inline char * dirname(char *file) {
-	char buffer[_MAX_PATH] = { 0 };
-	char drive[_MAX_DRIVE];
-	char dir[_MAX_DIR];
-	char fname[_MAX_FNAME];
-	char ext[_MAX_EXT];
+	char drive[_MAX_DRIVE] = { 0 };
+	char dir[_MAX_DIR] = { 0 };
+	char fname[_MAX_FNAME], ext[_MAX_EXT];
 	_splitpath_s(file, drive, _MAX_DRIVE, dir, _MAX_DIR, fname, _MAX_FNAME, ext, _MAX_EXT);
-	sprintf(buffer, "%s%s", drive, dir);
-	return &buffer[0];
+	if (dir && strlen(dir) && dir[strlen(dir)-1] == '\\') {
+		dir[strlen(dir) - 1] = '\0';
+	}
+	sprintf(dirname_buffer, "%s%s", drive, dir);
+	return &dirname_buffer[0];
 }
 #endif
 

util.c

@@ -161,12 +161,12 @@ void get_defconfig_path(char *out, size_t bufsize, char *argv0)
 	char *cmd = strdup(argv0);
 	char *dir = dirname(cmd);
 	const char *sep = strstr(dir, "\\") ? "\\" : "/";
+	struct stat info = { 0 };
 #ifdef WIN32
 	snprintf(out, bufsize, "%s\\cpuminer\\cpuminer-conf.json", getenv("APPDATA"));
 #else
 	snprintf(out, bufsize, "%s\\.cpuminer\\cpuminer-conf.json", getenv("HOME"));
 #endif
-	struct stat info;
 	if (dir && stat(out, &info) != 0) {
 		snprintf(out, bufsize, "%s%scpuminer-conf.json", dir, sep);
 	}