Build: POSIX shell isn't required if scripts are disabled.

INSTALL

diff --git a/INSTALL b/INSTALL
index ee32289..cb7f9bf 100644
--- a/INSTALL
+++ b/INSTALL
@@ -474,7 +474,8 @@
     to POSIX. The configure script tries to find such a shell. If
     it fails, you can force the shell to be used by passing
     gl_cv_posix_shell=/path/to/posix-sh as an argument to the configure
-    script.
+    script. Alternatively you can omit the installation of scripts and
+    this error by passing --disable-scripts to configure.
 
 
 4.3. configure works but build fails at crc32_x86.S

configure.ac

diff --git a/configure.ac b/configure.ac
index c0247b5..0efaaec 100644
--- a/configure.ac
+++ b/configure.ac
@@ -474,7 +474,7 @@
 
 echo
 gl_POSIX_SHELL
-if test -z "$POSIX_SHELL" ; then
+if test -z "$POSIX_SHELL" && test "x$enable_scripts" = xyes ; then
 	AC_MSG_ERROR([No POSIX conforming shell (sh) was found.])
 fi