• Patch configure instead of configure.in so we can avoid USES=autoreconf. An obscure macro is used in configure.in that autoreconf cannot find anywhere (ACX_CHECK_CXX_FLAGS).
• Disable a test for libcharset from converters/libiconv, so the code will use nl_langinfo from libc instead.
• Remove unneeded CONFIGURE_ENV, CPPFLAGS and LDFLAGS.

Reported by: antoine