Pseudoportable C script pattern
It's not guaranteed that $TMP_PROGRAM_FILE is on the $PATH, so you need to either set the $PATH or use an absolute path for $TMP_PROGRAM_FILE.

You have problems with mktemp.




-t option: It means different things on GNU/Linux mktemp(1) and Mac OS X mktemp(1).

On GNU/Linux:

-t    interpret TEMPLATE as a single file name component,
      relative to a directory: $TMPDIR, if set; else the
      directory specified via -p; else /tmp [deprecated]


On OS X:

mktemp [-t prefix] template …
mktemp -t prefix

    -t prefix
            Generate a template (using the supplied prefix and TMPDIR if set) to create a filename tem-plate. template.
            plate.


Perhaps the confusion is the reason why the GNU/Linux man page indicates that it is deprecated.  I think you just want to run mktemp TEMPLATE without the -t option.
Cleanup: Use trap "rm $TMP_SOURCE_FILE $TMP_PROGRAM_FILE" EXIT as a more robust way to delete the temporary files, in case your script aborts before reaching the rm commands.
.c suffix:  By writing TMP_SOURCE_FILE="$(mktemp -t sourceXXXX).c", you end up getting mktemp to create the file sourceXXXX.  That file does not get cleaned up.  Also, when you do cat &gt; $TMP_SOURCE_FILE, you may be creating sourceXXXX.c, or worse, truncating an existing file.

On GNU/Linux, a remedy would be to use the --suffix .c option.  Unfortunately, the BSD/OS X version doesn't support it.  One workaround is to rename the file after creation using mv -i — which might fail, but at least it's secure.

A better workaround would be to use gcc -x c to tell GCC that it is C source code, without considering the filename extension.

An even better solution would be…
Avoid $TMP_SOURCE_FILE altogether: gcc can take its source code from its standard input!  Use - as the filename.

gcc -o "$TMP_PROGRAM_FILE" -x c - &lt;&lt;- END_OF_SOURCE
…
END_OF_SOURCE