configure: Generate more friendly Makefile.config with separated CFLAGS

Each dependency now gets its own variable in the resulting
Makefile.config to make it much easier to debug where the various
flags came from in the case of any problems.

diff --git a/configure b/configure
index 65411956f0ebd35c8a5958f6aa685c9af0247586..1097b7c426d1a8df84d50b73450378736cda5409 100755 (executable)
--- a/configure
+++ b/configure
@@ -32,8 +32,8 @@ printf "Checking for Xapian development files... "
 if xapian-config --version > /dev/null 2>&1; then
     printf "Yes.\n"
     have_xapian=1
-    cxxflags="${cxxflags} $(xapian-config --cxxflags)"
-    ldflags="${ldflags} $(xapian-config --libs)"
+    xapian_cxxflags=$(xapian-config --cxxflags)
+    xapian_ldflags=$(xapian-config --libs)
 else
     printf "No.\n"
     have_xapian=0
@@ -44,8 +44,8 @@ printf "Checking for GMime 2.4 development files... "
 if pkg-config --modversion gmime-2.4 > /dev/null 2>&1; then
     printf "Yes.\n"
     have_gmime=1
-    cflags="${cflags} $(pkg-config --cflags gmime-2.4)"
-    ldflags="${ldflags} $(pkg-config --libs gmime-2.4)"
+    gmime_cflags=$(pkg-config --cflags gmime-2.4)
+    gmime_ldflags=$(pkg-config --libs gmime-2.4)
 else
     printf "No.\n"
     have_gmime=0
@@ -56,8 +56,8 @@ printf "Checking for talloc development files... "
 if pkg-config --modversion talloc > /dev/null 2>&1; then
     printf "Yes.\n"
     have_talloc=1
-    cflags="${cflags} $(pkg-config --cflags talloc)"
-    ldflags="${ldflags} $(pkg-config --libs talloc)"
+    talloc_cflags=$(pkg-config --cflags talloc)
+    talloc_ldflags=$(pkg-config --libs talloc)
 else
     printf "No.\n"
     have_talloc=0
@@ -69,7 +69,7 @@ printf "Checking for valgrind development files... "
 if pkg-config --modversion valgrind > /dev/null 2>&1; then
     printf "Yes.\n"
     have_valgrind=1
-    cflags="${cflags} $(pkg-config --cflags valgrind)"
+    valgrind_cflags=$(pkg-config --cflags valgrind)
 else
     printf "No (but that's fine).\n"
     have_valgrind=0
@@ -178,9 +178,30 @@ emacs_lispdir=${emacs_lispdir}
 # build its own version)
 HAVE_GETLINE = ${have_getline}
 
-# Various flags needed to compile and link against the dependencies of
-# notmuch.
-override CFLAGS += ${cflags} -DHAVE_VALGRIND=${have_valgrind} -DHAVE_GETLINE=\$(HAVE_GETLINE)
-override CXXFLAGS += ${cflags} ${cxxflags}
-override LDFLAGS += ${ldflags}
+# Flags needed to compile and link against Xapian
+XAPIAN_CXXFLAGS = ${xapian_cxxflags}
+XAPIAN_LDFLAGS = ${xapian_ldflags}
+
+# Flags needed to compile and link against GMime-2.4
+GMIME_CFLAGS = ${gmime_cflags}
+GMIME_LDFLAGS = ${gmime_ldflags}
+
+# Flags needed to compile and linke against talloc
+TALLOC_CFLAGS = ${talloc_cflags}
+TALLOC_LDFLAGS = ${talloc_ldflags}
+
+# Whether valgrind header files are available
+HAVE_VALGRIND = ${have_valgrind}
+
+# And if so, flags needed at compile time for valgrind macros
+VALGRIND_CFLAGS = ${valgrind_cflags}
+
+# Combined flags for compiling and linking against all of the above
+override CFLAGS += -DHAVE_GETLINE=\$(HAVE_GETLINE) \$(GMIME_CFLAGS)      \\
+                  \$(TALLOC_CFLAGS) -DHAVE_VALGRIND=\$(HAVE_VALGRIND)   \\
+                  \$(VALGRIND_CFLAGS)
+override CXXFLAGS += -DHAVE_GETLINE=\$(HAVE_GETLINE) \$(GMIME_CFLAGS)    \\
+                    \$(TALLOC_CFLAGS) -DHAVE_VALGRIND=\$(HAVE_VALGRIND) \\
+                    \$(VALGRIND_CFLAGS) \$(XAPIAN_CXXFLAGS)
+override LDFLAGS += \$(GMIME_LDFLAGS) \$(TALLOC_LDFLAGS) \$(XAPIAN_LDFLAGS)
 EOF