First commit.

This version works, although there is only one line of documentation/debug.

git-hash.c

@@ -0,0 +1,46 @@
+#include <stdio.h>
+#include <string.h>
+
+char static str[137];
+
+int main()
+{
+    if(!is_in_git_repo())
+        return 0;
+    strcpy(str, "#if defined _INC_GIT_HASH\n");
+    strcat(str, "    #endinput\n");
+    strcat(str, "#else\n");
+    strcat(str, "    #define _INC_GIT_HASH\n");
+    strcat(str, "#endif\n\n");
+    strcat(str, "#define GitHash ");
+    getGitSha(str);
+    store_data("githash.inc", str);
+    //printf("%d\n", strlen(str)); //Debug function, to count the string size if there are any changes to 'str'.
+}
+
+getGitSha(char *target)
+{
+    FILE *sha = popen("git rev-parse --verify HEAD -q", "r");
+    char buf[40];
+    while (fgets(buf, sizeof(buf), sha) != 0) {
+        strcat(target, buf);
+    }
+    pclose(sha);
+}
+
+int is_in_git_repo()
+{
+    if(system("git rev-parse --verify HEAD -q"))
+        return 0;
+    return 1;
+}
+
+store_data(const char *filepath, const char *data)
+{
+    FILE *fp = fopen(filepath, "w");
+    if (fp != NULL)
+    {
+        fputs(data, fp);
+        fclose(fp);
+    }
+}