cmake: detect `libssh` via `pkg-config`

Also:
- fix broken libssh `pkg-config` behaviour on old Linux.
  (when found, `LIBSSH_LINK_LIBRARIES` remains undefined.)

- delete manual libssh config from Old Linux CI job,
  it's no longer necessary.

Closes #14199

diff --git a/.github/workflows/linux-old.yml b/.github/workflows/linux-old.yml
index ecb5968f47840b8ef0655ae1b6d609f71012e4cd..0aec21683c5c084026a3b06d013f37e1d07b7768 100644 (file)
--- a/.github/workflows/linux-old.yml
+++ b/.github/workflows/linux-old.yml
@@ -89,8 +89,7 @@ jobs:
         run: |
           mkdir bld-cares
           cd bld-cares
-          cmake .. -DCMAKE_UNITY_BUILD=ON -DCURL_WERROR=ON -DBUILD_SHARED_LIBS=ON -DENABLE_ARES=ON -DCURL_ZSTD=ON -DCURL_USE_GSSAPI=ON -DCURL_USE_LIBSSH2=OFF \
-            -DUSE_LIBSSH=ON '-DCMAKE_C_FLAGS=-I/usr/include -L/usr/lib -lssh'
+          cmake .. -DCMAKE_UNITY_BUILD=ON -DCURL_WERROR=ON -DBUILD_SHARED_LIBS=ON -DENABLE_ARES=ON -DCURL_ZSTD=ON -DCURL_USE_GSSAPI=ON -DCURL_USE_LIBSSH2=OFF -DCURL_USE_LIBSSH=ON
 
       - name: 'build'
         run: |

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8b864a8febd2c17531e868320bf450402fa2a205..580cc4357d752cc0e4d15d6619c62572816a617c 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -994,11 +994,21 @@ endif()
 option(CURL_USE_LIBSSH "Use libssh" OFF)
 mark_as_advanced(CURL_USE_LIBSSH)
 if(NOT USE_LIBSSH2 AND CURL_USE_LIBSSH)
-  find_package(libssh CONFIG)
+  find_package(libssh CONFIG QUIET)
   if(libssh_FOUND)
     message(STATUS "Found libssh ${libssh_VERSION}")
-    # Use imported target for include and library paths.
-    list(APPEND CURL_LIBS ssh)
+  else()
+    find_package(PkgConfig QUIET)
+    pkg_check_modules(LIBSSH "libssh")
+    if(LIBSSH_FOUND)
+      include_directories(${LIBSSH_INCLUDE_DIRS})
+    endif()
+  endif()
+  if(libssh_FOUND OR LIBSSH_FOUND)
+    if(NOT DEFINED LIBSSH_LINK_LIBRARIES)
+      set(LIBSSH_LINK_LIBRARIES "ssh")  # for find_package() with broken pkg-config (e.g. linux-old CI workflow)
+    endif()
+    list(APPEND CURL_LIBS ${LIBSSH_LINK_LIBRARIES})
     list(APPEND LIBCURL_PC_REQUIRES_PRIVATE "libssh")
     set(USE_LIBSSH ON)
   endif()