sispmctl: fix compilation error with musl

Unpatched compile fails because <sys/types.h> is not included
in <usb.h> (provided by "libusb-compat") and consequently
the 'u_int*_t' types are not found.

This should probably better be fixed in the core "libusb-compat"
package instead.

Signed-off-by: Richard Kunze <richard.kunze@web.de>

utils/sispmctl/Makefile

@@ -43,6 +43,7 @@ define Package/sispmctl/description
  multiple SIS-PM devices, too.
 endef
 
+TARGET_CFLAGS += -D_GNU_SOURCE
 CONFIGURE_ARGS += \
 	--enable-webless \
 	--disable-dependency-tracking

utils/sispmctl/patches/001-fix-includes.patch

@@ -0,0 +1,25 @@
+--- a/src/sispm_ctl.c
++++ b/src/sispm_ctl.c
+@@ -33,6 +33,7 @@
+ #include <stdlib.h>
+ #include <unistd.h>
+ #include <time.h>
++#include <sys/types.h>
+ #include <usb.h>
+ #include <assert.h>
+ #include "sispm_ctl.h"
+--- a/src/main.c
++++ b/src/main.c
+@@ -34,11 +34,11 @@
+ #define __USE_XOPEN
+ #include <time.h>
+ #include <signal.h>
+-#include <usb.h>
+ #include <assert.h>
+ #include <getopt.h>
+ #include <sys/types.h>
+ #include <sys/socket.h>
++#include <usb.h>
+ 
+ #include <fcntl.h>
+