configure.ac: Improve check for libusb-1.0.

PKG_CHECK_MODULES() checks for libusb-1.0 via pkg-config already, no
need to use a "manual" additional check via AC_CHECK_LIB() just to set
HAVE_LIBUSB_1_0 in config.h.

This helps with cross-compiling setups, among other things.

diff --git a/configure.ac b/configure.ac
index 950a6ca3c488844703111c19e03785fa93f133b5..3cf4f9b797ff4e6d4b44d71c0e3a0de39ae5a932 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -249,7 +249,7 @@ PKG_CHECK_MODULES([gthread], [gthread-2.0 >= 2.22.0],
        [CFLAGS="$CFLAGS $gthread_CFLAGS"; LIBS="$LIBS $gthread_LIBS";
        SR_PKGLIBS="$SR_PKGLIBS gthread-2.0"])
 
-# libusb is only needed for some hardware drivers.
+# libusb-1.0 is only needed for some hardware drivers.
 if test "x$LA_ASIX_SIGMA" != xno \
    -o "x$LA_CHRONOVU_LA8" != xno \
    -o "x$LA_FX2LAFW" != xno \
@@ -266,7 +266,11 @@ if test "x$LA_ASIX_SIGMA" != xno \
                        [CFLAGS="$CFLAGS $libusb_CFLAGS";
                        LIBS="$LIBS $libusb_LIBS";
                        SR_PKGLIBS="$SR_PKGLIBS libusb-1.0"])
-               AC_CHECK_LIB(usb-1.0, libusb_init)
+               # Define HAVE_LIBUSB_1_0 in config.h if we found libusb-1.0.
+               if test "x$libusb_CFLAGS" != "x"; then
+                       AC_DEFINE_UNQUOTED(HAVE_LIBUSB_1_0, [1],
+                               [Specifies whether we have a libusb.h header.])
+               fi
                ;;
        esac
 fi