pass user/maintainer provided CXXFLAGS to the Scintilla build process

 * Usually, Scintilla will now be built with -O2
 * this can improve performance significantly over the standard Scintilla -Os
   (up to 10%).
 * this also allows link-time-optimizing both Scintilla and SciTECO
   (which are linked statically) by adding -flto to CFLAGS, CXXFLAGS and LDFLAGS.
   Link-time-optimization will both reduce the total binary size
   and improve performance slightly since scintilla_send_message() can be
   inlined.
   An -O3 optimized Scintilla when linked with LTO results in an only 300kb
   larger SciTECO binary.
 * the highest possible optimization thus requires the following maintainer
   flags on the ./configure command line:
   CFLAGS="-O3 -mtune=native -march=native -flto"
   CXXFLAGS="-O3 -mtune=native -march=native -flto"
   LDFLAGS="-flto"
 * Windows and Debian builds use link-time-optimization now.
   On Windows - where we link in everything statically - building
   the dependant libraries with -flto could improve performance
   even more.
 * Debian builds respect the default hardening flags of the build
   server now. This should ensure that SciTECO is built for the
   correct architecture at the recommended optimization level etc.

1 files changed, 8 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index d44689b..56e61c9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -19,6 +19,14 @@ AC_CONFIG_HEADERS([config.h])
 AC_CANONICAL_BUILD
 AC_CANONICAL_HOST
 
+# Use the user provided CXXFLAGS for Scintilla as well.
+# This makes sure that the same optimizations are applied
+# to SciTECO and Scintilla.
+# We cannot pass CXXFLAGS directly to Scintilla since
+# we modify it during library checking.
+SCINTILLA_CXXFLAGS="$CXXFLAGS"
+AC_SUBST(SCINTILLA_CXXFLAGS)
+
 # Automake build flag substitutions.
 # Necessary so we can change their default values here
 AC_SUBST(AM_CPPFLAGS)