setup.sh: Only link files if the program is available.

diff --git a/setup.sh b/setup.sh
index 538c0794899e9794ce4c2932690da9c8b66882b5..593677c58f2809ae4377c0ae9b1d1ff9d12ce3ec 100755 (executable)
--- a/setup.sh
+++ b/setup.sh
@@ -21,10 +21,16 @@
 . ../lib.sh
 
 # gdb, GNU debugger.
-link gdbinit ~/.gdbinit
+if installed gdb; then
+    link gdbinit ~/.gdbinit
+fi
 
 # Maxima, a symbolic algebra program.
-link maxima ~/.maxima
+if installed maxima; then
+    link maxima ~/.maxima
+fi
 
 # perlcritic to check Perl programs for common problems.
-link perl/perlcriticrc ~/.perlcriticrc
+if installed perlcritic; then
+    link perl/perlcriticrc ~/.perlcriticrc
+fi