We've had multiple people getting obscure build failures for gnome-shell because on Arch linux, install is in /bin/install not /usr/bin/install. (Don't know why, not really my concern.)

The fix in bug 364465 was to add a preprocessor define, but that's not really a solution in my opinion. I could make our build-setup script try to detect the location and set the preprocessor define, but I'd much rather that jhbuild just go it right.

Searching $PATH seems reasonable, along the line of:

-  return execv (args[0], args);
+  return execvp (args[0], args);

(Obviously changing args[0]). If that was considered an unacceptable performance hit, you could stat /usr/bin/install first, before going the general route, but just using $PATH seems most expected.

For bonus points, check the return value of exec and print an error message :-)