Disable c asserts when building without "--enable-debug"

[Algunenano]

In our configure we try to disable C asserts when not building in debug mode:

AC_ARG_ENABLE([debug], AC_HELP_STRING([--enable-debug], [Enable debugging code and flags]),
	[ENABLE_DEBUG=1], [ENABLE_DEBUG=0])

if test $ENABLE_DEBUG -eq 1; then
    AC_DEFINE([PARANOIA_LEVEL], [10], [Enable use of memory checks])
    CFLAGS="$CFLAGS -g"
else
    AC_DEFINE([PARANOIA_LEVEL], [0], [Disable use of memory checks])
    AC_DEFINE([NDEBUG], [0], [Disable C asserts])
fi

I don't know what AC_DEFINE([NDEBUG], [0], [Disable C asserts]) is doing, probably nothing, but I still have asserts enabled in my release builds. I suggest adding -DNDEBUG to the CPPFLAGS directly instead.

I'm considering this as an enhancement since someone might be surprised by the change on the default, but I believe this was the intention all along.

[Algunenano]

PR in ​https://github.com/postgis/postgis/pull/518

[Raúl Marín <git@…>]

In 651add11/git:

Disable C asserts when building without "—enable-debug"

Closes ​https://github.com/postgis/postgis/pull/518
Closes #4589