libtiff: autoconf: Add --disable-opengl option

From b63e40603b709767084657fef75aab00fb9a26e4 Mon Sep 17 00:00:00 2001
From: Roger Leigh <[EMAIL REDACTED]>
Date: Sun, 29 May 2022 12:05:27 +0100
Subject: [PATCH] autoconf: Add --disable-opengl option

---
 configure.ac | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/configure.ac b/configure.ac
index 23e834a2..7706011b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -927,22 +927,28 @@ dnl ---------------------------------------------------------------------------
 
 HAVE_OPENGL=no
 
+AC_ARG_ENABLE(opengl,
+	      AS_HELP_STRING([--disable-opengl],
+			     [disable OpenGL usage (required by tiffgt, enabled by default)]),,)
 
-AC_PATH_XTRA
+if test "x$enable_opengl" != "xno" ; then
 
-dnl AX_CHECK_GL sets GL_CFLAGS & GL_LIBS.  Also PTHREAD_LIBS,
-dnl PTHREAD_CFLAGS, & PTHREAD_CC as a side-effect
-AX_CHECK_GL
+  AC_PATH_XTRA
 
-dnl AX_CHECK_GLU sets GLU_CFLAGS & GLU_LIBS
-AX_CHECK_GLU
+  dnl AX_CHECK_GL sets GL_CFLAGS & GL_LIBS.  Also PTHREAD_LIBS,
+  dnl PTHREAD_CFLAGS, & PTHREAD_CC as a side-effect
+  AX_CHECK_GL
 
-dnl AX_CHECK_GLUT sets GLUT_CFLAGS & GLUT_LIBS
-AX_CHECK_GLUT
+  dnl AX_CHECK_GLU sets GLU_CFLAGS & GLU_LIBS
+  AX_CHECK_GLU
 
-if test "$no_x" != "yes" -a "$no_gl" != "yes" \
-	-a "$no_glu" != "yes" -a "$no_glut" != "yes" ; then
-  HAVE_OPENGL=yes
+  dnl AX_CHECK_GLUT sets GLUT_CFLAGS & GLUT_LIBS
+  AX_CHECK_GLUT
+
+  if test "$no_x" != "yes" -a "$no_gl" != "yes" \
+      -a "$no_glu" != "yes" -a "$no_glut" != "yes" ; then
+    HAVE_OPENGL=yes
+  fi
 fi
 
 AM_CONDITIONAL(HAVE_OPENGL, test "$HAVE_OPENGL" = "yes")