standardize warning flags everywhere

I'd like to enable -Wextra as well, but that creates some false
positives.

I've at least made my changes clean w.r.t. -Wextra.

Now we have 4 remaining warnings with gcc 9.3 that seem genuine. Need to
fix those.

src/Makefile

@@ -8,7 +8,7 @@
 PLAT= none
 
 CC= gcc
-CFLAGS= -g -O2 -Wall -Wpedantic $(MYCFLAGS)
+CFLAGS= -g -O2 -Wall -Wpedantic -Wshadow $(MYCFLAGS)
 AR= ar rc
 RANLIB= ranlib
 RM= rm -f

src/kilo.c

@@ -1119,7 +1119,7 @@ void edit(lua_State* L, char* filename, const char* message) {
     }
 }
 
-void resumeEdit(lua_State* L, char* filename) {
+void resumeEdit(lua_State* L) {
     Quit = 0;
     editorSetStatusMessage(Previous_error);
     while(!Quit) {

src/lcurses/compat-5.2.c

@@ -530,7 +530,7 @@ void lua_len (lua_State *L, int i) {
     case LUA_TUSERDATA:
       if (luaL_callmeta(L, i, "__len"))
         break;
-      /* maybe fall through */
+    /* maybe fall through */
     default:
       luaL_error(L, "attempt to get length of a %s value",
                  lua_typename(L, lua_type(L, i)));

src/lcurses/window.c

@@ -1304,7 +1304,7 @@ Read a character from the window input.
 @see curses.echo
 @see keypad
 */
-extern void switch_to_editor (lua_State *L, const char *message);
+extern void switch_to_editor (lua_State *L);
 static int
 Wgetch(lua_State *L)
 {
@@ -1316,7 +1316,7 @@ Wgetch(lua_State *L)
 	if (c == 24)  /* ctrl-x */
 		exit(0);
 	if (c == 5)  /* ctrl-e */
-		switch_to_editor(L, "");
+		switch_to_editor(L);
 	/* handle other standard menu hotkeys here */
 
 	return pushintresult(c);

src/ldebug.c

@@ -412,7 +412,7 @@ Instruction symbexec (const Proto *pt, int lastpc, int reg) {
       case OP_FORLOOP:
       case OP_FORPREP:
         checkreg(pt, a+3);
-        /* go through */
+        /* fall through */
       case OP_JMP: {
         int dest = pc+1+b;
         /* not full check and jump is forward and do not skip `lastpc'? */

src/lua.c

@@ -326,7 +326,7 @@ void save_to_current_definition_and_editor_buffer (lua_State *L, const char *def
 }
 
 
-static void read_contents (lua_State *L, char *filename, char *out) {
+static void read_contents (char *filename, char *out) {
     int infd = open(filename, O_RDONLY);
     read(infd, out, 8190);  /* TODO: handle overly large file */
     close(infd);
@@ -373,15 +373,12 @@ void editor_refresh_buffer (void) {
   clearEditor();
   editorOpen("teliva_editbuffer");
 }
-extern void resumeEdit (lua_State *L, char *filename);
-void editor_resume (lua_State *L) {
-  resumeEdit(L, "teliva_editbuffer");
-}
+extern void resumeEdit (lua_State *L);
 
 
 int load_editor_buffer_to_current_definition_in_image(lua_State *L) {
   char new_contents[8192] = {0};
-  read_contents(L, "teliva_editbuffer", new_contents);
+  read_contents("teliva_editbuffer", new_contents);
   update_definition(L, Current_definition, new_contents);
   save_image(L);
   /* reload binding */
@@ -402,7 +399,7 @@ void edit_image (lua_State *L, const char *definition) {
       break;
     Previous_error = lua_tostring(L, -1);
     if (Previous_error == NULL) Previous_error = "(error object is not a string)";
-    editor_resume(L);
+    resumeEdit(L);
     lua_pop(L, 1);
   }
 }
@@ -550,7 +547,7 @@ int browse_image (lua_State *L) {
 
 
 extern void cleanup_curses (void);
-void switch_to_editor (lua_State *L, const char *message) {
+void switch_to_editor (lua_State *L) {
   /* clobber the app's ncurses colors; we'll restart the app when we rerun it. */
   for (int i = 0; i < 8; ++i)
     init_pair(i, i, -1);
@@ -581,13 +578,13 @@ static int collectargs (char **argv, int *pi, int *pv, int *pe) {
         return i;
       case 'i':
         notail(argv[i]);
-        *pi = 1;  /* go through */
+        *pi = 1;  /* fall through */
       case 'v':
         notail(argv[i]);
         *pv = 1;
         break;
       case 'e':
-        *pe = 1;  /* go through */
+        *pe = 1;  /* fall through */
       case 'l':
         if (argv[i][2] == '\0') {
           i++;

src/luasec/Makefile

@@ -9,7 +9,7 @@ OBJS= \
  config.o  \
  ec.o
 
-WARN=-Wall -pedantic
+WARN=-Wall -Wpedantic -Wshadow
 
 BSD_CFLAGS=-O2 -fPIC $(WARN) $(INCDIR) $(DEFS)
 BSD_LDFLAGS=-O -fPIC -shared $(LIBDIR)

src/luasec/context.c

@@ -1,7 +1,7 @@
 /*--------------------------------------------------------------------------
  * LuaSec 1.0.2
  *
- * Copyright (C) 2014-2021 Kim Alvefur, Paul Aurich, Tobias Markmann, 
+ * Copyright (C) 2014-2021 Kim Alvefur, Paul Aurich, Tobias Markmann,
  *                         Matthew Wild.
  * Copyright (C) 2006-2021 Bruno Silvestre.
  *
@@ -120,7 +120,7 @@ static const SSL_METHOD* str2method(const char *method, int *vmin, int *vmax)
  */
 static int set_verify_flag(const char *str, int *flag)
 {
-  if (!strcmp(str, "none")) { 
+  if (!strcmp(str, "none")) {
     *flag |= SSL_VERIFY_NONE;
     return 1;
   }
@@ -132,7 +132,7 @@ static int set_verify_flag(const char *str, int *flag)
     *flag |= SSL_VERIFY_CLIENT_ONCE;
     return 1;
   }
-  if (!strcmp(str, "fail_if_no_peer_cert")) { 
+  if (!strcmp(str, "fail_if_no_peer_cert")) {
     *flag |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
     return 1;
   }
@@ -153,7 +153,7 @@ static int passwd_cb(char *buf, int size, int flag, void *udata)
        lua_pop(L, 1);  /* Remove the result from the stack */
        return 0;
     }
-    /* fallback */
+    /* fall through */
   case LUA_TSTRING:
     strncpy(buf, lua_tostring(L, -1), size);
     lua_pop(L, 1);  /* Remove the result from the stack */
@@ -398,8 +398,8 @@ static int load_key(lua_State *L)
   case LUA_TFUNCTION:
     SSL_CTX_set_default_passwd_cb(ctx, passwd_cb);
     SSL_CTX_set_default_passwd_cb_userdata(ctx, L);
-    /* fallback */
-  case LUA_TNIL: 
+    /* fall through */
+  case LUA_TNIL:
     if (SSL_CTX_use_PrivateKey_file(ctx, filename, SSL_FILETYPE_PEM) == 1)
       lua_pushboolean(L, 1);
     else {
@@ -543,7 +543,7 @@ static int set_mode(lua_State *L)
   lua_pushboolean(L, 0);
   lua_pushfstring(L, "invalid mode (%s)", str);
   return 1;
-}   
+}
 
 /**
  * Configure DH parameters.
@@ -677,7 +677,7 @@ static int alpn_cb(SSL *s, const unsigned char **out, unsigned char *outlen,
   if (ret != OPENSSL_NPN_NEGOTIATED) {
     lua_pop(L, 2);
     return SSL_TLSEXT_ERR_NOACK;
-  } 
+  }
 
   // Copy the result because lua_pop() can collect the pointer
   ctx->alpn = malloc(*outlen);

src/luasocket/makefile

@@ -174,7 +174,7 @@ SO_linux=so
 O_linux=o
 CC_linux=gcc
 DEF_linux=-DLUASOCKET_$(DEBUG)
-CFLAGS_linux=-g -O2 -Wall -Wpedantic -Wshadow -Wextra $(LUAINC:%=-I%) $(DEF)
+CFLAGS_linux= -g -O2 -Wall -Wpedantic -Wshadow -Wextra $(LUAINC:%=-I%) $(DEF)
 LDFLAGS_linux= -o
 LD_linux=ld
 SOCKET_linux=usocket.o