Fix more warnings

Makefile

@@ -10,8 +10,6 @@ ifeq ($(CC), clang)
 		-Weverything                  \
 		-Wno-missing-prototypes       \
 		-Wno-unused-parameter         \
-		-Wno-sign-compare             \
-		-Wno-implicit-fallthrough     \
 		-Wno-sign-conversion          \
 		-Wno-conversion               \
 		-Wno-disabled-macro-expansion \

ftepp.c

@@ -1115,7 +1115,7 @@ static bool ftepp_hash(ftepp_t *ftepp)
                 ftepp_error(ftepp, "unrecognized preprocessor directive: `%s`", ftepp_tokval(ftepp));
                 return false;
             }
-            break;
+            /* break; never reached */
         default:
             ftepp_error(ftepp, "unexpected preprocessor token: `%s`", ftepp_tokval(ftepp));
             return false;

ir.c

@@ -3167,7 +3167,7 @@ bool ir_builder_generate(ir_builder *self, const char *filename)
 const char *qc_opname(int op)
 {
     if (op < 0) return "<INVALID>";
-    if (op < ( sizeof(asm_instr) / sizeof(asm_instr[0]) ))
+    if (op < (int)( sizeof(asm_instr) / sizeof(asm_instr[0]) ))
         return asm_instr[op].m;
     switch (op) {
         case VINSTR_PHI:  return "PHI";

main.c

@@ -256,7 +256,7 @@ static bool options_parse(int argc, char **argv) {
                 case 'h':
                     usage();
                     exit(0);
-                    break;
+                    /* break; never reached because of exit(0) */
 
                 case 'E':
                     opts_pp_only = true;

util.c

@@ -270,8 +270,8 @@ void util_endianswap(void *m, int s, int l) {
     if(*((char *)&s))
         return;
 
-    for(; w < l; w++) {
+    for(; w < (size_t)l; w++) {
-        for(;  i < s << 1; i++) {
+        for(;  i < (size_t)(s << 1); i++) {
             unsigned char *p = (unsigned char *)m+w*s;
             unsigned char  t = p[i];
             p[i]             = p[s-i-1];