depends: add _LIBCPP_ENABLE_ASSERTIONS to DEBUG mode

See
https://releases.llvm.org/16.0.0/projects/libcxx/docs/UsingLibcxx.html#assertions-mode
for more info.

depends/hosts/linux.mk

@@ -17,7 +17,7 @@ linux_release_CXXFLAGS=$(linux_release_CFLAGS)
 linux_debug_CFLAGS=-O1
 linux_debug_CXXFLAGS=$(linux_debug_CFLAGS)
 
-linux_debug_CPPFLAGS=-D_GLIBCXX_DEBUG -D_GLIBCXX_DEBUG_PEDANTIC
+linux_debug_CPPFLAGS=-D_GLIBCXX_DEBUG -D_GLIBCXX_DEBUG_PEDANTIC -D_LIBCPP_ENABLE_ASSERTIONS=1
 
 ifeq (86,$(findstring 86,$(build_arch)))
 i686_linux_CC=gcc -m32