Only use mallopt M_MMAP_THRESHOLD if glibc

TODO

@@ -211,3 +211,5 @@ Make it possible to change replay duration of the "save 1 min" and "save 10 min"
 
 If replay duration is set below the "save 1 min" or "save 10 min" then gray them out and when hovering over those buttons
     show a tooltip that says that those buttons cant be used because the replay duration in replay settings is set to a lower value than that (and display the replay duration there).
+
+Add content framerate mode for wayland with desktop portal capture when it has been added to gpu-screen-recorder and if it works.

src/main.cpp

@@ -195,7 +195,9 @@ enum class LaunchAction {
 
 int main(int argc, char **argv) {
     setlocale(LC_ALL, "C"); // Sigh... stupid C
+#ifdef __GLIBC__
     mallopt(M_MMAP_THRESHOLD, 65536);
+#endif
 
     if(geteuid() == 0) {
         fprintf(stderr, "Error: don't run gsr-ui as the root user\n");