graphviz-2.47.1-bashisms.patch

diff -Naur a/configure.ac b/configure.ac
--- a/configure.ac	2019-07-13 03:14:04.000000000 +0000
+++ b/configure.ac	2020-05-15 19:44:57.715169627 +0000
@@ -315,7 +315,7 @@
 dnl ===========================================================================
 dnl Set GCC compiler flags
 
-if [test "${GCC}" == "yes"]
+if [test "${GCC}" = "yes"]
 then
   # Enable common warnings flags
   CFLAGS="${CFLAGS} -Wall"