From: Matthew Fernandez <matthew.fernandez@gmail.com>
Date: Mon, 2 Jan 2023 17:24:43 +0000 (-0800)
Subject: Autotools: discover libANN manually if ann.pc is missing
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=3faa5adc9ab57d480eed15951c0bc6cc18c4269f;p=graphviz

Autotools: discover libANN manually if ann.pc is missing

On Debian and Debian derivatives (e.g. Ubuntu) the libann and libann-dev
packages ship without an ann.pc file to support `pkg-config`. As a result of
this, `pkg-config` cannot find libANN and concludes it is not installed.

This change teaches the Autotools build system how to discover libANN manually
if the `pkg-config` technique fails. Note that we need to use `AC_CHECK_FILE`
instead of `AC_CHECK_HEADER` because libANN is in C++.

Gitlab: closes #1835
---

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1be153c54..075c03563 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   from ~3.8MB to 32MB. #1710
 - Reserved stack size on macOS for the `dot` binary when built with CMake has
   been increased from 8MB to 32MB. #1710
+- The Autotools build system can now find libANN on Debian-based operating
+  systems, enabling compilation of libmingle and `mingle`. #1835
 
 ### Fixed
 
diff --git a/ci/tests.py b/ci/tests.py
index 73f917fc1..e2167a2a8 100644
--- a/ci/tests.py
+++ b/ci/tests.py
@@ -115,12 +115,6 @@ def test_existence(binary: str):
 
   os_id = _freedesktop_os_release().get("ID")
 
-  # FIXME: Remove skip when
-  # https://gitlab.com/graphviz/graphviz/-/issues/1835 is fixed
-  if os_id == "ubuntu" and binary == "mingle" and not is_cmake():
-    check_that_tool_does_not_exist(binary, os_id)
-    pytest.skip(f"mingle is not built for {os_id} (#1835)")
-
   # FIXME: Remove skip when
   # https://gitlab.com/graphviz/graphviz/-/issues/1834 is fixed
   if os_id == "centos" and binary == "smyrna":
diff --git a/configure.ac b/configure.ac
index ef8a8113f..2439de5e7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1924,7 +1924,18 @@ else
     AC_SUBST([ANN_CFLAGS])
     AC_SUBST([ANN_LIBS])
   ],[
-    use_ann="No (no ann.pc found)"
+    # fall back discovery for the Debian ecosystem which does not ship an ann.pc
+    AC_CHECK_FILE(/usr/include/ANN/ANN.h, [
+      ANN_CFLAGS= # nothing required
+      AC_CHECK_LIB(ann, ann_visit_pts, [
+        ANN_LIBS=-lann
+        use_ann="Yes"
+      ], [
+        use_ann="No (no ann.pc or libANN found)"
+      ])
+    ], [
+      use_ann="No (no ann.pc or ANN.h found)"
+    ])
   ])
 fi
 AM_CONDITIONAL(WITH_ANN, [test x"${use_ann%% *}" = "xYes"])