autoconf: Add checking for unsetenv function

diff --git a/Makefile b/Makefile
index a566bd9aedaa6aa7fdc26cc94a77e07e4e220973..13aa24f91849859400f2c507f2b2d60cf3fae1dc 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -38,6 +38,8 @@ all::
 #
 # Define NO_SETENV if you don't have setenv in the C library.
 #
+# Define NO_UNSETENV if you don't have unsetenv in the C library.
+#
 # Define NO_MKDTEMP if you don't have mkdtemp in the C library.
 #
 # Define NO_SYMLINK_HEAD if you never want .git/HEAD to be a symbolic link.