From 5a472d6aaa2922939b28bfc8186e7341ec1fc222 Mon Sep 17 00:00:00 2001
From: Rob Browning <rlb@defaultvalue.org>
Date: Sun, 21 Jun 2020 11:47:02 -0500
Subject: [PATCH] configure: check for <readline.h> vs <readline/readline.h>

The readline docs (man and info pages) indicate that we should use

  #include <readline/readline.h>
  #include <readline/history.h>

Unfortunately, it appears that on a number of plaforms pkg-config
--cflags actually returns a -I value that requires

  #include <readline.h>
  #include <history.h>

So make an even bigger mess in config/configure to accomodate either
possibility.

Signed-off-by: Rob Browning <rlb@defaultvalue.org>
Tested-by: Rob Browning <rlb@defaultvalue.org>
---
 config/configure   | 68 ++++++++++++++++++++++++++++++++++++----------
 lib/bup/_helpers.c |  9 ++++--
 2 files changed, 60 insertions(+), 17 deletions(-)

diff --git a/config/configure b/config/configure
index c7ab50c..33670dd 100755
--- a/config/configure
+++ b/config/configure
@@ -14,13 +14,20 @@ bup_find_prog()
 
 bup_try_c_code()
 {
-    local code="$1" tmpdir rc
+    local code="$1" tmpdir rc cflags=''
     if test -z "$code"; then
         AC_FAIL "No code provided to test compile"
     fi
+    case "$#" in
+        1) ;;
+        2) cflags="$2" ;;
+        *)
+            AC_FAIL "Invald call to bup_try_c_code" "$@"
+            ;;
+    esac
     tmpdir="$(mktemp -d "bup-try-c-compile-XXXXXXX")" || exit $?
     echo "$code" > "$tmpdir/test.c" || exit $?
-    $AC_CC -Wall -Werror -c -o "$tmpdir/test" "$tmpdir/test.c"
+    $AC_CC -Wall -Werror $cflags -c -o "$tmpdir/test" "$tmpdir/test.c"
     rc=$?
     rm -r "$tmpdir" || exit $?
     return $rc
@@ -167,29 +174,60 @@ if test "$ac_defined_HAVE_MINCORE"; then
     fi
 fi
 
+
 TLOGN "checking for readline"
+bup_have_readline=''
+bup_readline_includes_in_subdir=''
+bup_readline_via_pkg_config=''
 if pkg-config readline; then
     bup_readline_cflags="$(pkg-config readline --cflags)" || exit $?
     bup_readline_ldflags="$(pkg-config readline --libs)" || exit $?
-    bup_have_readline=1
-    AC_DEFINE BUP_HAVE_READLINE 1
-    TLOG ' (yes, pkg-config)'
-elif bup_try_c_code '#include <readline/readline.h>'; then
-    bup_readline_cflags=''
-    bup_readline_ldflags=-lreadline
-    bup_have_readline=1
+    # It looks like it's not uncommon for pkg-config to provide a -I
+    # that doesn't support the documentation's specified #include
+    # <readline/readline.h>.  See what's really going on.
+    if bup_try_c_code '#include <readline/readline.h>' "$bup_readline_cflags"
+    then
+        bup_have_readline=1
+        bup_readline_includes_in_subdir=1
+    elif bup_try_c_code '#include <readline.h>' "$bup_readline_cflags"
+    then
+        bup_have_readline=1
+    fi
+    if test "$bup_have_readline"; then
+        bup_readline_via_pkg_config=1
+    else
+        bup_readline_cflags=''
+        bup_readline_ldflags=''
+    fi
+fi
+if ! test "$bup_have_readline"; then
+    if bup_try_c_code '#include <readline/readline.h>'; then
+        bup_readline_ldflags=-lreadline
+        bup_have_readline=1
+        bup_readline_includes_in_subdir=1
+    elif bup_try_c_code '#include <readline.h>'; then
+        bup_readline_ldflags=-lreadline
+        bup_have_readline=1
+    fi
+fi
+if test "$bup_have_readline"; then
     AC_DEFINE BUP_HAVE_READLINE 1
-    TLOG ' (yes)'
-else
-    bup_readline_cflags=''
-    bup_readline_ldflags=''
-    bup_have_readline=''
-    TLOG ' (no)'
+    if test "$bup_readline_includes_in_subdir"; then
+        AC_DEFINE BUP_READLINE_INCLUDES_IN_SUBDIR 1
+    fi
+    if test "$bup_readline_via_pkg_config"; then
+        TLOG ' (yes, pkg-config)'
+    else
+        TLOG ' (yes)'
+    fi
 fi
+
+
 AC_SUB bup_readline_cflags "$bup_readline_cflags"
 AC_SUB bup_readline_ldflags "$bup_readline_ldflags"
 AC_SUB bup_have_readline "$bup_have_readline"
 
+
 AC_CHECK_FIELD stat st_atim sys/types.h sys/stat.h unistd.h
 AC_CHECK_FIELD stat st_mtim sys/types.h sys/stat.h unistd.h
 AC_CHECK_FIELD stat st_ctim sys/types.h sys/stat.h unistd.h
diff --git a/lib/bup/_helpers.c b/lib/bup/_helpers.c
index b2eb781..ed08aa3 100644
--- a/lib/bup/_helpers.c
+++ b/lib/bup/_helpers.c
@@ -54,8 +54,13 @@
 #ifdef BUP_HAVE_READLINE
 # pragma GCC diagnostic push
 # pragma GCC diagnostic ignored "-Wstrict-prototypes"
-# include <readline/readline.h>
-# include <readline/history.h>
+# ifdef BUP_READLINE_INCLUDES_IN_SUBDIR
+#   include <readline/readline.h>
+#   include <readline/history.h>
+# else
+#   include <readline.h>
+#   include <history.h>
+# endif
 # pragma GCC diagnostic pop
 #endif
 
-- 
2.39.2