package/linux-tools: fix tmon static build with uclibc

Pass LDFLAGS (which will contain -static) to fix the following tmon
static build failure with uclibc:

/home/autobuild/autobuild/instance-3/output-1/host/bin/x86_64-buildroot-linux-uclibc-gcc -O3 -Wall -Wshadow -W -Wformat -Wimplicit-function-declaration -Wimplicit-int  -D VERSION=\"1.0\"   tmon.o tui.o sysfs.o pid.o  -o tmon -lm -lpthread -lpanel -lncurses
/home/autobuild/autobuild/instance-3/output-1/host/lib/gcc/x86_64-buildroot-linux-uclibc/10.3.0/../../../../x86_64-buildroot-linux-uclibc/bin/ld: /home/autobuild/autobuild/instance-3/output-1/host/lib/gcc/x86_64-buildroot-linux-uclibc/10.3.0/libgcc.a(unwind-dw2-fde-dip.o): in function `_Unwind_Find_FDE':
/home/autobuild/autobuild/instance-3/output-1/build/host-gcc-final-10.3.0/build/x86_64-buildroot-linux-uclibc/libgcc/../../../libgcc/unwind-dw2-fde-dip.c:469: undefined reference to `dl_iterate_phdr'

Fixes:
 - http://autobuild.buildroot.org/results/58f4cdb734b68afb02595d004e7ca19a15d1abcc

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
(cherry picked from commit 2cbcdbf0add46da55020eb56b5e4b974b44e958b)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/linux-tools/linux-tool-tmon.mk.in

@@ -9,6 +9,7 @@ LINUX_TOOLS += tmon
 TMON_DEPENDENCIES = host-pkgconf ncurses
 TMON_MAKE_OPTS = $(LINUX_MAKE_FLAGS) \
 	CC=$(TARGET_CC) \
+	LDFLAGS="$(TARGET_LDFLAGS)" \
 	PKG_CONFIG_PATH=$(STAGING_DIR)/usr/lib/pkgconfig
 
 ifeq ($(BR2_TOOLCHAIN_HAS_SSP),)