link libm to the duktape shared libraries; unbreaks at least polkit & gdm

Index: Makefile.sharedlibrary
--- Makefile.sharedlibrary.orig
+++ Makefile.sharedlibrary
@@ -70,12 +70,12 @@ all: libduktape.$(SO_REALNAME_SUFFIX) libduktaped.$(SO
 # to $INSTALL_PREFIX/include on installation.
 
 libduktape.$(SO_REALNAME_SUFFIX):
-	$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) -shared -fPIC -Wall -Wextra -Os -Wl,$(LD_SONAME_ARG),libduktape.$(SO_SONAME_SUFFIX) \
-		-o $@ $(DUKTAPE_SRCDIR)/duktape.c
+	$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) -shared -fPIC -Wall -Wextra -Wl,$(LD_SONAME_ARG),libduktape.so.$(REAL_VERSION) \
+		-o $@ $(DUKTAPE_SRCDIR)/duktape.c -lm
 
 libduktaped.$(SO_REALNAME_SUFFIX):
-	$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) -shared -fPIC -g -Wall -Wextra -Os -Wl,$(LD_SONAME_ARG),libduktaped.$(SO_SONAME_SUFFIX) \
-		-o $@ $(DUKTAPE_SRCDIR)/duktape.c
+	$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) -shared -fPIC -g -Wall -Wextra -Wl,$(LD_SONAME_ARG),libduktaped.$(REAL_VERSION) \
+		-o $@ $(DUKTAPE_SRCDIR)/duktape.c -lm
 
 duktape.pc:
 	sed -e "s|@PREFIX@|$(INSTALL_PREFIX)|" \
@@ -99,6 +99,6 @@ install: libduktape.$(SO_REALNAME_SUFFIX) libduktaped.
 	mkdir -p $(DESTDIR)$(INSTALL_PREFIX)/include/
 	cp $(DUKTAPE_SRCDIR)/duktape.h $(DUKTAPE_SRCDIR)/duk_config.h $(DESTDIR)$(INSTALL_PREFIX)/include/
 
-CCOPTS = -I./examples/cmdline
-duk:
-	$(CC) $(CCOPTS) -I$(INSTALL_PREFIX)/include -L$(INSTALL_PREFIX)$(LIBDIR) -Wall -Wextra -Os -o $@ ./examples/cmdline/duk_cmdline.c -lduktape -lm
+CCOPTS = -I./examples/cmdline -Isrc
+duk: libduktape.$(SO_REALNAME_SUFFIX)
+	$(CC) $(CCOPTS) -Wall -Wextra ${CFLAGS} -o $@ ./examples/cmdline/duk_cmdline.c -L. -lduktape -lm
