iproute2: tc: reduce size of dynamic symbol table

In the case of SHARED_LIBS=y, don't use -export-dynamic to place *all*
symbols into the dynamic symbol table. Instead, use --dynamic-list to
export a smaller set of symbols similar to that defined in static-syms.h
in the case of SHARED_LIBS=n, avoiding an 11 KB tc package size increase.
The symbol set is based on that required by the only plugin, m_xt.so.

Also increment PKG_RELEASE.

Signed-off-by: Tony Ambardar <itugrok@yahoo.com>
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com> [PKG_RELEASE fixup]

package/network/utils/iproute2/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=iproute2
 PKG_VERSION:=4.20.0
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
 PKG_SOURCE_URL:=@KERNEL/linux/utils/net/iproute2

package/network/utils/iproute2/patches/175-reduce-dynamic-syms.patch

@@ -0,0 +1,44 @@
+--- a/tc/Makefile
++++ b/tc/Makefile
+@@ -107,7 +107,7 @@ LDLIBS += -L. -lm
+ 
+ ifeq ($(SHARED_LIBS),y)
+ LDLIBS += -ldl
+-LDFLAGS += -Wl,-export-dynamic
++LDFLAGS += -Wl,--dynamic-list=dynsyms.list
+ endif
+ 
+ TCLIB := tc_core.o
+@@ -137,7 +137,7 @@ MODDESTDIR := $(DESTDIR)$(LIBDIR)/tc
+ all: tc $(TCSO)
+ 
+ tc: $(TCOBJ) $(LIBNETLINK) libtc.a
+-	$(QUIET_LINK)$(CC) $^ $(LDFLAGS) $(LDLIBS) -o $@
++	$(QUIET_LINK)$(CC) $(filter-out dynsyms.list, $^) $(LDFLAGS) $(LDLIBS) -o $@
+ 
+ libtc.a: $(TCLIB)
+ 	$(QUIET_AR)$(AR) rcs $@ $^
+@@ -159,6 +159,7 @@ install: all
+ clean:
+ 	rm -f $(TCOBJ) $(TCLIB) libtc.a tc *.so emp_ematch.yacc.h; \
+ 	rm -f emp_ematch.yacc.*
++	rm -f dynsyms.list
+ 
+ q_atm.so: q_atm.c
+ 	$(QUIET_CC)$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) -shared -fpic -o q_atm.so q_atm.c -latm
+@@ -198,4 +199,15 @@ static-syms.h: $(wildcard *.c)
+ 		sed -n '/'$$s'[^ ]* =/{s:.* \([^ ]*'$$s'[^ ]*\) .*:extern char \1[] __attribute__((weak)); if (!strcmp(sym, "\1")) return \1;:;p}' $$files ; \
+ 	done > $@
+ 
++else
++
++tc: dynsyms.list
++dynsyms.list: $(wildcard *.c)
++	files="$(filter-out $(patsubst %.so,%.c,$(TCSO)), $^)" ; \
++	echo "{" > $@ ; \
++	for s in `grep -B 3 '\<dlsym' $$files | sed -n '/snprintf/{s:.*"\([^"]*\)".*:\1:;s:%s::;p}'` ; do \
++		sed -n '/'$$s'[^ ]* =/{s:.* \([^ ]*'$$s'[^ ]*\) .*:\1;:;p}' $$files ; \
++	done >> $@ ; \
++	echo "show_stats; print_tm; parse_rtattr; get_u32; matches; addattr_l; addattr_nest; addattr_nest_end; };" >> $@
++
+ endif