configure.ac: check require_basic_egl only if egl enabled

Otherwise the configuration fails when building independant libs
like vdpau, vaapi or omx

Fixes: 1ac40173c2a ("configure.ac: simplify EGL requirements for
drivers dependent on EGL")

Signed-off-by: Leo Liu <leo.liu@amd.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Cc: "17.0" <mesa-stable@lists.freedesktop.org>
(cherry picked from commit 5398d006de3d2bd668e3fc4b80a3de0c101a3e43)
[Emil Velikov: resolve trivial conflicts]
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>

Conflicts:
	configure.ac
diff --git a/configure.ac b/configure.ac
index 8448736..399166a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2328,7 +2328,9 @@
             PKG_CHECK_MODULES([AMDGPU], [libdrm_amdgpu >= $LIBDRM_AMDGPU_REQUIRED])
             require_libdrm "radeonsi"
             radeon_gallium_llvm_check $LLVM_REQUIRED_RADEONSI "radeonsi"
-            require_basic_egl "radeonsi"
+            if test "x$enable_egl" = xyes; then
+                require_basic_egl "radeonsi"
+            fi
             ;;
         xnouveau)
             HAVE_GALLIUM_NOUVEAU=yes