diff --git a/fluid/Fl_Function_Type.cxx b/fluid/Fl_Function_Type.cxx
index eb90b4f15..5a4ad35dc 100644
--- a/fluid/Fl_Function_Type.cxx
+++ b/fluid/Fl_Function_Type.cxx
@@ -681,7 +681,7 @@ void Fl_Comment_Type::read_property(const char *c) {
 #include "comments.h"
 
 static void load_comments_preset(Fl_Preferences &menu) {
-  static char *predefined_comment[] = {
+  static const char * const predefined_comment[] = {
     "GNU Public License/GPL Header",  "GNU Public License/GPL Footer",
     "GNU Public License/LGPL Header", "GNU Public License/LGPL Footer",
     "FLTK/Header", "FLTK/Footer" };
diff --git a/src/Fl_BMP_Image.cxx b/src/Fl_BMP_Image.cxx
index a7ca84523..6f6c3e23d 100644
--- a/src/Fl_BMP_Image.cxx
+++ b/src/Fl_BMP_Image.cxx
@@ -82,7 +82,7 @@ Fl_BMP_Image::Fl_BMP_Image(const char *bmp) // I - File to read
 		byte;		// Byte in image
   uchar		*ptr;		// Pointer into pixels
   uchar		colormap[256][3];// Colormap
-  uchar		mask = 0;	// single bit mask follows image data
+  uchar		havemask = 0;	// single bit mask follows image data
 
   // Open the file...
   if ((fp = fopen(bmp, "rb")) == NULL) return;
@@ -134,7 +134,7 @@ Fl_BMP_Image::Fl_BMP_Image(const char *bmp) // I - File to read
       int Bpp = depth/8;
       int maskSize = (((w()*Bpp+3)&~3)*h()) + (((((w()+7)/8)+3)&~3)*h());
       if (maskSize==2*dataSize) {
-        mask = 1;
+        havemask = 1;
 	h(h()/2);
 	bDepth = 4;
       }
@@ -329,7 +329,7 @@ Fl_BMP_Image::Fl_BMP_Image(const char *bmp) // I - File to read
 	    *ptr++ = colormap[temp][2];
 	    *ptr++ = colormap[temp][1];
 	    *ptr++ = colormap[temp][0];
-	    if (mask) ptr++;
+	    if (havemask) ptr++;
 	  }
 
 	  if (!compression) {
@@ -375,7 +375,7 @@ Fl_BMP_Image::Fl_BMP_Image(const char *bmp) // I - File to read
     }
   }
   
-  if (mask) {
+  if (havemask) {
     for (y = h() - 1; y >= 0; y --) {
       ptr = (uchar *)array + y * w() * d() + 3;
       for (x = w(), bit = 128; x > 0; x --, ptr+=bDepth) {
diff --git a/src/Fl_JPEG_Image.cxx b/src/Fl_JPEG_Image.cxx
index aab9fd5b6..e4cc88d13 100644
--- a/src/Fl_JPEG_Image.cxx
+++ b/src/Fl_JPEG_Image.cxx
@@ -73,15 +73,17 @@ struct fl_jpeg_error_mgr {
 //
 
 #ifdef HAVE_LIBJPEG
-static void
-fl_jpeg_error_handler(j_common_ptr dinfo) {	// I - Decompressor info
-  longjmp(((fl_jpeg_error_mgr *)(dinfo->err))->errhand_, 1);
-  return;
-}
+extern "C" {
+  static void
+  fl_jpeg_error_handler(j_common_ptr dinfo) {	// I - Decompressor info
+    longjmp(((fl_jpeg_error_mgr *)(dinfo->err))->errhand_, 1);
+    return;
+  }
 
-static void
-fl_jpeg_output_handler(j_common_ptr dinfo) {	// I - Decompressor info
-  return;
+  static void
+  fl_jpeg_output_handler(j_common_ptr dinfo) {	// I - Decompressor info
+    return;
+  }
 }
 #endif // HAVE_LIBJPEG
 
diff --git a/src/Fl_PNM_Image.cxx b/src/Fl_PNM_Image.cxx
index 09c4fc93e..866c16aea 100644
--- a/src/Fl_PNM_Image.cxx
+++ b/src/Fl_PNM_Image.cxx
@@ -83,7 +83,7 @@ Fl_PNM_Image::Fl_PNM_Image(const char *name)	// I - File to read
   format = atoi(lineptr);
   while (isdigit(*lineptr)) lineptr ++;
 
-  if (format == 7) lineptr = "";
+  if (format == 7) lineptr = (char *)"";
 
   while (lineptr != NULL && w() == 0) {
     if (*lineptr == '\0' || *lineptr == '#') {
diff --git a/test/editor.cxx b/test/editor.cxx
index d27b95e70..9d9759779 100644
--- a/test/editor.cxx
+++ b/test/editor.cxx
@@ -150,13 +150,14 @@ const char         *code_types[] = {	// List of known C/C++ types...
 // 'compare_keywords()' - Compare two keywords...
 //
 
-int
-compare_keywords(const void *a,
-                 const void *b) {
-  return (strcmp(*((const char **)a), *((const char **)b)));
+extern "C" {
+  int
+  compare_keywords(const void *a,
+                   const void *b) {
+    return (strcmp(*((const char **)a), *((const char **)b)));
+  }
 }
 
-
 //
 // 'style_parse()' - Parse text and produce style data.
 //