libsigc++: fix tarball name and use new-style options

fixes #2341

actually updating to >= 2.10 breaks glibmm etc until #2174 is completed

src/libsigc++.mk

@@ -5,14 +5,16 @@ $(PKG)_WEBSITE  := https://libsigc.sourceforge.io/
 $(PKG)_IGNORE   :=
 $(PKG)_VERSION  := 2.4.0
 $(PKG)_CHECKSUM := 7593d5fa9187bbad7c6868dce375ce3079a805f3f1e74236143bceb15a37cd30
-$(PKG)_GH_CONF  := libsigcplusplus/libsigcplusplus/tags
+$(PKG)_GH_CONF  := libsigcplusplus/libsigcplusplus/releases,,,99,,.tar.xz
+$(PKG)_SUBDIR   := $(PKG)-$($(PKG)_VERSION)
 $(PKG)_DEPS     := cc
 
 define $(PKG)_BUILD
-    cd '$(1)' && ./configure \
+    cd '$(BUILD_DIR)' && '$(SOURCE_DIR)/configure' \
         $(MXE_CONFIGURE_OPTS) \
         CXX='$(TARGET)-g++' \
         PKG_CONFIG='$(PREFIX)/bin/$(TARGET)-pkg-config' \
         MAKE=$(MAKE)
-    $(MAKE) -C '$(1)' -j '$(JOBS)' install $(MXE_DISABLE_CRUFT)
+    $(MAKE) -C '$(BUILD_DIR)' -j '$(JOBS)' $(MXE_DISABLE_CRUFT)
+    $(MAKE) -C '$(BUILD_DIR)' -j 1 install $(MXE_DISABLE_CRUFT)
 endef