Fix compiler warnings, backported from 1.4 (master)

Also update CHANGES file.

The compiler warnings were issued by MinGW with gcc 9.2.0.

Note: There are lots of compiler warnings left when building with
  Visual Studio and/or NMake but these will not be fixed in 1.3.9.
  All warnings have been fixed in 1.4.0 (current git 'master').

CHANGES

@@ -8,6 +8,8 @@ Highlights in this release:
   - Update bundled libraries to current versions.
   - Introduce bundled image library "prefixing" to avoid conflicts
     with system libraries.
+  - New CMake option FLTK_MSVC_RUNTIME_DLL selects Visual Studio
+    Runtime (DLL or static) if built with CMake 3.15 or later
 
 Details:
 
@@ -28,6 +30,7 @@ Details:
     Fix several compiler warnings
     Update bundled image libraries and zlib to current versions
     Update README, README.CMake.txt, and some support files
+    Fix compiler warnings: backported from 1.4 (git 'master')
 
   ManoloFLTK:
     macOS platform: Issue #325 "Disabling IM disables Greek and Cyrillic layouts"
@@ -35,11 +38,16 @@ Details:
     Fix issue #373 apparent with macOS platform and SDK ≤ 10.13
     Issue #452: Fl::get_font_name failure on OS-X.
     Issue #454: crash in Fl::get_font_name().
-    Issue #469: Fl_Sys_Menu_Bar menu item shortcuts using Escape or Tab don't work on Mac
+    Issue #469: Fl_Sys_Menu_Bar menu item shortcuts using Esc or Tab don't work on Mac
     Fix "Focus is lost leaving full screen on macOS 13" (#608)
     Add support of macOS Ventura 13.0 and macOS Sonoma 14.0
     macOS: remove configure option --enable-x11 and CMake OPTION_APPLE_X11;
       this functionality remains in FLTK 1.4.
+    configure.ac: make sure local-png and local-zlib always run together
+    Remove the -mwindows argument from CFLAGS and CXXFLAGS
+
+Matthias Melcher:
+    Issue #188: Fix reference counts and search for Fl_Shared_Image original
 
   YX:
     Fix IME problem (issue #270)

src/Fl_Native_File_Chooser_WIN32.cxx

@@ -120,12 +120,11 @@ static void dnullcat(char*&wp, const char *string, int n = -1 ) {
     }
   }
 
-  if ( n == -1 ) n = (int) strlen(string);
+  memcpy(wp2, string, inlen); // use memcpy to avoid compiler warning
-  strncpy(wp2, string, n);
 
   // Leave string double-null terminated
-  *(wp2+n+0) = '\0';
+  *(wp2+inlen+0) = '\0';
-  *(wp2+n+1) = '\0';
+  *(wp2+inlen+1) = '\0';
   //DEBUG printf("DEBUG: dnullcat OUT: <"); dnullprint(wp); printf(">\n\n");
 }
 
@@ -691,12 +690,12 @@ void Fl_Native_File_Chooser::add_filter(const char *name_in,	// name of filter (
   // No name? Make one..
   char name[1024];
   if ( !name_in || name_in[0] == '\0' ) {
-    sprintf(name, "%.*s Files", int(sizeof(name)-10), winfilter);
+    snprintf(name, sizeof(name), "%.*s Files", int(sizeof(name)-10), winfilter);
   } else {
     if ((strlen(name_in)+strlen(winfilter)+3) < sizeof(name)) {
-      sprintf(name, "%s (%s)", name_in, winfilter);
+      snprintf(name, sizeof(name), "%s (%s)", name_in, winfilter);
     } else {
-      sprintf(name, "%.*s", int(sizeof(name)), name_in);
+      snprintf(name, sizeof(name), "%.*s", int(sizeof(name))-1, name_in);
     }
   }
   dnullcat(_parsedfilt, name);

src/forms_timer.cxx

@@ -47,8 +47,8 @@ void fl_gettime(long* sec, long* usec) {
   *sec = now->tm_sec + 60*now->tm_min + 3600*now->tm_hour + 24*3600*now->tm_yday;
   *usec = 0;
 # else
-  struct timeb tp;
+  struct _timeb tp;
-  ftime(&tp);
+  _ftime(&tp);
   *sec = (long) tp.time;
   *usec = tp.millitm * 1000;
 # endif