cocoa: fix UTF8String misuse + move AVFoundation link to HAVE_MICROPHONE

Two issues on the PPC/Leopard make build:

    cocoa_common.m:1062: warning: passing argument 1 of
        'config_file_new_from_string' discards qualifiers from
        pointer target type
    ld: framework not found AVFoundation

ISSUE 1: config_file_new_from_string() takes (char*) and the header
explicitly documents that it mutates its input in place.  -[NSString
UTF8String] returns an Apple-owned buffer that is not writable.
Passing it through directly is undefined behavior, not merely a
qualifier warning - modern Obj-C with tagged-pointer string
optimizations may crash or corrupt other strings.

Follow the pattern already used at tasks/task_autodetect.c:374:
strdup() the UTF-8 copy, pass the duplicate, free() it after.  This
fix matters on every platform, not just PPC.

ISSUE 2: AVFoundation is 10.7+ and doesn't exist on the 10.5 SDK.
Makefile.common linked it unconditionally whenever HAVE_COREAUDIO
was set, even though the base coreaudio.c path doesn't use it;
only coreaudio_mic_macos.m does.  HAVE_MICROPHONE was already auto-
disabled on pre-10.7 by c11279c, so the AVFoundation link is
unnecessary on those targets and breaks the build.

Move '-framework AVFoundation' into the ifeq ($(HAVE_MICROPHONE), 1)
block.  Modern builds with microphone support still link it;
pre-10.7 builds (microphone auto-disabled) skip it.  Accelerate and
AudioToolbox stay in the outer block - both are 10.3+ and always
needed when coreaudio is built.

Author: LibretroAdmin

Makefile.common

@@ -814,9 +814,14 @@ ifeq ($(HAVE_COREAUDIO), 1)
    OBJ += audio/drivers/coreaudio.o
 ifeq ($(HAVE_MICROPHONE), 1)
    OBJ += audio/drivers/coreaudio_mic_macos.o
+   # AVFoundation is 10.7+ and only needed by the microphone driver.
+   # The base coreaudio.c path doesn't use it, so keep it out of the
+   # link line on targets without microphone support (e.g. pre-10.7
+   # / Tiger / Leopard / PowerPC).
+   LIBS += -framework AVFoundation
 endif
    HAVE_COREAUDIO_LIBS = 1
-   LIBS += -framework AudioToolbox -framework AVFoundation -framework Accelerate
+   LIBS += -framework AudioToolbox -framework Accelerate
 endif
 
 ifeq ($(HAVE_COREAUDIO3), 1)

ui/drivers/cocoa/cocoa_common.m

@@ -1059,8 +1059,17 @@ bool cocoa_get_metrics(
    NSString *backup = [[NSUserDefaults standardUserDefaults] stringForKey:@FILE_PATH_MAIN_CONFIG];
    if ([backup length] > 0)
    {
-      conf = config_file_new_from_string([backup UTF8String], path_get(RARCH_PATH_CONFIG));
-      config_set_int(conf, "bundle_assets_extract_last_version", 0);
+      /* config_file_new_from_string() takes (char*) and mutates it in
+       * place.  -[NSString UTF8String] returns an Apple-owned buffer
+       * that is not writable, so we must strdup() first and free
+       * after. */
+      char *backup_copy = strdup([backup UTF8String]);
+      if (backup_copy)
+      {
+         conf = config_file_new_from_string(backup_copy, path_get(RARCH_PATH_CONFIG));
+         config_set_int(conf, "bundle_assets_extract_last_version", 0);
+         free(backup_copy);
+      }
    }
    return conf;
 }