some cross-platform portability changes

CMakeLists.txt

@@ -15,6 +15,7 @@ include(CheckFunctionExists)
 include(GNUInstallDirs)
 
 # Check if system has strtonum
+check_function_exists(strndup HAVE_STRNDUP)
 check_function_exists(strtonum HAVE_STRTONUM)
 check_function_exists(reallocarray HAVE_REALLOCARRAY)
 
@@ -29,6 +30,10 @@ include_directories(${GD_INCLUDE_DIRS})
 set(SRC src/clean.c src/drawchar.c src/fonts.c src/error.c src/loadfile.c src/init.c src/output.c src/savefile.c)
 set(LOADERS src/loaders/ansi.c src/loaders/artworx.c src/loaders/binary.c src/loaders/icedraw.c src/loaders/pcboard.c src/loaders/tundra.c src/loaders/xbin.c)
 
+if(NOT HAVE_STRNDUP)
+ set(SRC ${SRC} compat/strndup.c)
+endif()
+
 if(NOT HAVE_STRTONUM)
  set(SRC ${SRC} compat/strtonum.c)
 endif()

compat/strndup.c

@@ -0,0 +1,22 @@
+// SPDX-FileCopyrightText: 2024 Martin J. Fiedler <[email protected]>
+// SPDX-License-Identifier: MIT
+
+#include <stdio.h>
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "strndup.h"
+
+char *strndup(const char *str, size_t size) {
+ char *buffer;
+ size_t srclen = strlen(str);
+ if (srclen < size) { size = srclen; }
+ buffer = (char*) malloc(size + 1);
+ if (buffer) {
+ strncpy(buffer, str, size);
+ }
+ buffer[size] = '\0';
+ return buffer;
+}

compat/strndup.h

@@ -0,0 +1 @@
+char *strndup(const char *str, size_t size);

include/ansilove.h

@@ -23,7 +23,9 @@
 extern "C" {
 #endif
 
+#ifndef ANSILOVE_EXTERN
 #define ANSILOVE_EXTERN __attribute__((visibility("default")))
+#endif
 
 /* Version number */
 #define ANSILOVE_VERSION "1.4.1"

src/loaders/ansi.c

@@ -25,6 +25,10 @@
 #include "fonts.h"
 #include "output.h"
 
+#ifndef HAVE_STRNDUP
+#include "strndup.h"
+#endif
+
 #ifndef HAVE_STRTONUM
 #include "strtonum.h"
 #endif