From e3e0caa53eb04673341cae79e9a3e1bf0538cc93 Mon Sep 17 00:00:00 2001
From: Pieter Lexis <pieter.lexis@powerdns.com>
Date: Thu, 31 Mar 2016 08:54:20 +0200
Subject: [PATCH] Automatically detect protobuf (similar to Lua)

No need to `--enable-protobuf`. If you want to skip protobuf detection,
`--without-protobuf` is your friend. We also fail configure if
`--with-protobuf=yes` and protobuf is not found.
---
 configure.ac               |  3 +--
 m4/pdns_enable_protobuf.m4 | 14 --------------
 m4/pdns_with_protobuf.m4   | 27 +++++++++++++++++++++++++++
 3 files changed, 28 insertions(+), 16 deletions(-)
 delete mode 100644 m4/pdns_enable_protobuf.m4
 create mode 100644 m4/pdns_with_protobuf.m4

diff --git a/configure.ac b/configure.ac
index 1e7bb8d29..388e1c1da 100644
--- a/configure.ac
+++ b/configure.ac
@@ -176,6 +176,7 @@ AC_ARG_ENABLE([tools],
 AC_MSG_RESULT([$enable_tools])
 AM_CONDITIONAL([TOOLS], [test "x$enable_tools" != "xno"])
 
+PDNS_WITH_PROTOBUF
 
 for a in $modules $dynmodules; do
   case "$a" in
@@ -272,8 +273,6 @@ PDNS_ENABLE_COVERAGE
 PDNS_ENABLE_SANITIZERS
 PDNS_ENABLE_MALLOC_TRACE
 
-PDNS_ENABLE_PROTOBUF
-
 AC_SUBST(LIBS)
 
 AC_SUBST([AM_CPPFLAGS],
diff --git a/m4/pdns_enable_protobuf.m4 b/m4/pdns_enable_protobuf.m4
deleted file mode 100644
index 4c58899e8..000000000
--- a/m4/pdns_enable_protobuf.m4
+++ /dev/null
@@ -1,14 +0,0 @@
-AC_DEFUN([PDNS_ENABLE_PROTOBUF], [
-  AC_MSG_CHECKING([whether to enable protobuf support])
-  AC_ARG_ENABLE([protobuf],
-    AS_HELP_STRING([--enable-protobuf],[enable protobuf support @<:@default=no@:>@]),
-    [enable_protobuf=$enableval],
-    [enable_protobuf=no],
-  )
-  AC_MSG_RESULT([$enable_protobuf])
-  AS_IF([test "x$enable_protobuf" = "xyes"], [
-    PKG_CHECK_MODULES([PROTOBUF], [protobuf], [HAVE_PROTOBUF=1], [AC_MSG_ERROR([Could not find protobuf])])
-  ], [HAVE_PROTOBUF=0])
-  AM_CONDITIONAL([HAVE_PROTOBUF], [test "$HAVE_PROTOBUF" -eq 1])
-  AS_IF([test "$HAVE_PROTOBUF" -eq 1], [AC_DEFINE([HAVE_PROTOBUF], [1], [Define if using protobuf.])])
-])
diff --git a/m4/pdns_with_protobuf.m4 b/m4/pdns_with_protobuf.m4
new file mode 100644
index 000000000..39d4e1c96
--- /dev/null
+++ b/m4/pdns_with_protobuf.m4
@@ -0,0 +1,27 @@
+AC_DEFUN([PDNS_WITH_PROTOBUF], [
+  AC_MSG_CHECKING([if we need to link in protobuf])
+  AC_ARG_WITH([protobuf],
+    AS_HELP_STRING([--with-protobuf],[enable protobuf support @<:@default=auto@:>@]),
+    [with_protobuf=$withval],
+    [with_protobuf=auto],
+  )
+  AC_MSG_RESULT([$with_protobuf])
+
+  AS_IF([test "x$with_protobuf" != "xno"], [
+    AS_IF([test "x$with_protobuf" = "xyes" -o "x$with_protobuf" = "xauto"], [
+      PKG_CHECK_MODULES([PROTOBUF], [protobuf], [ ], [ ])
+      AC_CHECK_PROG([PROTOC], [protoc], [protoc])
+    ])
+  ])
+  AS_IF([test "x$with_protobuf" = "xyes"], [
+    AS_IF([test x"$PROTOBUF_LIBS" = "x"], [
+      AC_MSG_ERROR([Protobuf requested but libraries were not found])
+    ])
+    AS_IF([test x"$PROTOC" = "x"], [
+      AC_MSG_ERROR([Protobuf requested but the protobuf compiler was not found])
+    ])
+  ])
+  AM_CONDITIONAL([HAVE_PROTOBUF], [test x"$PROTOBUF_LIBS" != "x"])
+  AM_CONDITIONAL([HAVE_PROTOC], [test x"$PROTOC" != "x"])
+  AS_IF([test x"$PROTOBUF_LIBS" != "x"], [AC_DEFINE([HAVE_PROTOBUF], [1], [Define if using protobuf.])])
+])
-- 
2.40.0