+CFLAGS=${CFLAGS:--O2}
+CXXFLAGS=${CXXFLAGS:-\$(CFLAGS)}
+XAPIAN_CONFIG=${XAPIAN_CONFIG:-xapian-config-1.1 xapian-config}
+
+# We don't allow the EMACS or GZIP Makefile variables inherit values
+# from the environment as we do with CC and CXX above. The reason is
+# that these names as environment variables have existing uses other
+# than the program name that we want. (EMACS is set to 't' when a
+# shell is running within emacs and GZIP specifies arguments to pass
+# on the gzip command line).
+
+# Set the defaults for values the user can specify with command-line
+# options.
+PREFIX=/usr/local
+LIBDIR=
+
+usage ()
+{
+ cat <<EOF
+Usage: ./configure [options]...
+
+This script configures notmuch to build on your system.
+
+It verifies that dependencies are available, determines flags needed
+to compile and link against various required libraries, and identifies
+whether various system functions can be used or if locally-provided
+replacements will be built instead.
+
+Finally, it allows you to control various aspects of the build and
+installation process.
+
+First, some common variables can specified via environment variables:
+
+ CC The C compiler to use
+ CFLAGS Flags to pass to the C compiler
+ CXX The C++ compiler to use
+ CXXFLAGS Flags to pass to the C compiler
+ LDFLAGS Flags to pass when linking
+
+Each of these values can further be controlled by specifying them
+later on the "make" command line.
+
+Other environment variables can be used to control configure itself,
+(and for which there is no equivalent build-time control):
+
+ XAPIAN_CONFIG The program to use to determine flags for
+ compiling and linking against the Xapian
+ library. [$XAPIAN_CONFIG]
+
+Additionally, various options can be specified on the configure
+command line.
+
+ --prefix=PREFIX Install files in PREFIX [$PREFIX]
+
+By default, "make install" will install the resulting program to
+$PREFIX/bin, documentation to $PREFIX/man, etc. You can
+specify an installation prefix other than $PREFIX using
+--prefix, for instance:
+
+ ./configure --prefix=\$HOME
+
+Fine tuning of some installation directories is available:
+
+ --libdir=DIR Install libraries in LIBDIR [PREFIX/lib]
+
+EOF
+}
+
+# Parse command-line options
+for option; do
+ if [ "${option}" = '--help' ] ; then
+ usage
+ exit 0
+ elif [ "${option%%=*}" = '--prefix' ] ; then
+ PREFIX="${option#*=}"
+ elif [ "${option%%=*}" = '--libdir' ] ; then
+ LIBDIR="${option#*=}"
+ else
+ echo "Unrecognized option: ${option}."
+ echo "See:"
+ echo " $0 --help"
+ echo ""
+ exit 1
+ fi
+done