diff --git a/Makefile b/Makefile
index 125f1acf..0964a45e 100644
--- a/Makefile
+++ b/Makefile
@@ -26,7 +26,7 @@ PNGLDLIBS	:= `${PKG_CONFIG} --static --libs-only-l libpng`
 
 VERSION_STRING	:= `git describe --tags --dirty --always 2>/dev/null`
 
-WARNFLAGS	:= -Werror -Wall -Wpedantic
+WARNFLAGS	:= -Werror -Wall -Wextra -Wpedantic -Wno-sign-compare
 
 # Overridable CFLAGS
 CFLAGS		:= -g
diff --git a/src/asm/asmy.y b/src/asm/asmy.y
index ea964260..93d3f0f4 100644
--- a/src/asm/asmy.y
+++ b/src/asm/asmy.y
@@ -341,8 +341,9 @@ static void if_skip_to_else(void)
 				break;
 
 			case '\"':
-				src++;
+				src += 2;
 				inString = false;
+				break;
 
 			default:
 				src++;
diff --git a/src/asm/fstack.c b/src/asm/fstack.c
index 6b7141e9..19d58e20 100644
--- a/src/asm/fstack.c
+++ b/src/asm/fstack.c
@@ -257,8 +257,10 @@ FILE *fstk_FindFile(char *fname)
 		 * space had been available. Thus, a return value of `size` or
 		 * more means that the output was truncated.
 		 */
-		if (snprintf(path, sizeof(path), "%s%s", IncludePaths[i], fname)
-		    >= sizeof(path))
+		int fullpathlen = snprintf(path, sizeof(path), "%s%s",
+					   IncludePaths[i], fname);
+
+		if (fullpathlen >= (int)sizeof(path))
 			continue;
 
 		f = fopen(path, "rb");
diff --git a/src/asm/globlex.c b/src/asm/globlex.c
index 79a8583d..9dae47bc 100644
--- a/src/asm/globlex.c
+++ b/src/asm/globlex.c
@@ -216,7 +216,7 @@ uint32_t PutMacroArg(char *src, uint32_t size)
 	return 0;
 }
 
-uint32_t PutUniqueArg(char *src, uint32_t size)
+uint32_t PutUniqueArg(__attribute ((unused)) char *src, uint32_t size)
 {
 	char *s;
 
diff --git a/src/asm/main.c b/src/asm/main.c
index 4a551a88..3996ff89 100644
--- a/src/asm/main.c
+++ b/src/asm/main.c
@@ -225,7 +225,7 @@ void opt_AddDefine(char *s)
 
 static void opt_ParseDefines(void)
 {
-	int32_t i;
+	uint32_t i;
 
 	for (i = 0; i < cldefines_index; i += 2)
 		sym_AddString(cldefines[i], cldefines[i + 1]);
diff --git a/src/asm/symbol.c b/src/asm/symbol.c
index c673e10c..24bcb385 100644
--- a/src/asm/symbol.c
+++ b/src/asm/symbol.c
@@ -62,7 +62,7 @@ void helper_RemoveLeadingZeros(char *string)
 	memmove(string, new_beginning, strlen(new_beginning) + 1);
 }
 
-int32_t Callback_NARG(struct sSymbol *sym)
+int32_t Callback_NARG(__attribute__ ((unused)) struct sSymbol *sym)
 {
 	uint32_t i = 0;
 
@@ -673,7 +673,7 @@ void sym_AddReloc(char *tzSym)
 
 			struct sSymbol *parent = pScope->pScope ?
 						 pScope->pScope : pScope;
-			int32_t parentLen = localPtr - tzSym;
+			uint32_t parentLen = localPtr - tzSym;
 
 			if (strchr(localPtr + 1, '.') != NULL) {
 				fatalerror("'%s' is a nonsensical reference to a nested local symbol",
diff --git a/src/gfx/main.c b/src/gfx/main.c
index 6171676d..b58e39f8 100644
--- a/src/gfx/main.c
+++ b/src/gfx/main.c
@@ -53,6 +53,7 @@ int main(int argc, char *argv[])
 			break;
 		case 'F':
 			opts.hardfix = true;
+			/* fallthrough */
 		case 'f':
 			opts.fix = true;
 			break;