build.sh: Check for lex and yacc.

Warn the user, if lex(1) and yacc(1) cannot be found. This is not
necessarily an error, as flex(1) or bison(1) might be available.

As suggested by Kevin Trumbull (onebinary) on IRC.

Signed-off-by: Sebastian Harl <sh@tokkee.org>
Signed-off-by: Florian Forster <octo@huhu.verplant.org>

diff --git a/build.sh b/build.sh
index 3efb44f..cede2e4 100755 (executable)
--- a/build.sh
+++ b/build.sh
@@ -1,5 +1,15 @@
 #! /bin/sh
 
+if ! which lex > /dev/null 2>&1; then
+       echo "WARNING: lex not found!" >&2
+       echo "Make sure that you have a flex compatible tool available." >&2
+fi
+
+if ! which yacc > /dev/null 2>&1; then
+       echo "WARNING: yacc not found!" >&2
+       echo "Make sure that you have a GNU bison compatible tool available." >&2
+fi
+
 libtoolize=libtoolize
 
 if which glibtoolize > /dev/null 2>&1; then