Work around missing GLOBAL option of find_package in older CMake vers…

…ions

Also remove unnecessary direct dependency of SPQR on OpenMP.

Should fix #669.

CHOLMOD/CMakeLists.txt

@@ -88,7 +88,11 @@ if ( NOT SUITESPARSE_USE_OPENMP )
     set ( CHOLMOD_USE_OPENMP "OFF" CACHE STRING "" FORCE )
 endif ( )
 if ( CHOLMOD_USE_OPENMP )
-    find_package ( OpenMP COMPONENTS C GLOBAL )
+    if ( CMAKE_VERSION VERSION_LESS 3.24 )
+        find_package ( OpenMP COMPONENTS C )
+    else ( )
+        find_package ( OpenMP COMPONENTS C GLOBAL )
+    endif ( )
 else ( )
     # OpenMP has been disabled
     set ( OpenMP_C_FOUND OFF )

CMakeLists.txt

@@ -235,6 +235,23 @@ else ( )
     endif ( )
 endif ( )
 
+
+if ( CMAKE_VERSION VERSION_LESS 3.24 )
+    # work around missing GLOBAL option of find_package in older CMake versions
+    # If SuiteSparse is included as a sub-project in other projects, they might
+    # need to manually import the OpenMP targets for older CMake versions, too.
+    if ( "suitesparse_config" IN_LIST SUITESPARSE_ENABLE_PROJECTS
+            OR "cholmod" IN_LIST SUITESPARSE_ENABLE_PROJECTS
+            OR "graphblas" IN_LIST SUITESPARSE_ENABLE_PROJECTS
+            OR "paru" IN_LIST SUITESPARSE_ENABLE_PROJECTS )
+        find_package ( OpenMP COMPONENTS C )
+    endif ( )
+    if ( "paru" IN_LIST SUITESPARSE_ENABLE_PROJECTS )
+        find_package ( OpenMP COMPONENTS CXX )
+    endif ( )
+endif ( )
+
+
 #-------------------------------------------------------------------------------
 # include selected projects
 #-------------------------------------------------------------------------------

GraphBLAS/CMakeLists.txt

@@ -105,7 +105,11 @@ if ( NOT SUITESPARSE_USE_OPENMP )
     set ( GRAPHBLAS_USE_OPENMP "OFF" CACHE STRING "" FORCE )
 endif ( )
 if ( GRAPHBLAS_USE_OPENMP )
-    find_package ( OpenMP COMPONENTS C GLOBAL )
+    if ( CMAKE_VERSION VERSION_LESS 3.24 )
+        find_package ( OpenMP COMPONENTS C )
+    else ( )
+        find_package ( OpenMP COMPONENTS C GLOBAL )
+    endif ( )
 else ( )
     # OpenMP has been disabled.
     set ( OpenMP_C_FOUND OFF )

LAGraph/CMakeLists.txt

@@ -167,7 +167,11 @@ if ( COVERAGE )
     message ( STATUS "OpenMP disabled for test coverage" )
 else ( )
     if ( LAGRAPH_USE_OPENMP )
-        find_package ( OpenMP COMPONENTS C GLOBAL )
+        if ( CMAKE_VERSION VERSION_LESS 3.24 )
+            find_package ( OpenMP COMPONENTS C )
+        else ( )
+            find_package ( OpenMP COMPONENTS C GLOBAL )
+        endif ( )
         if ( OpenMP_C_FOUND AND BUILD_STATIC_LIBS )
             list ( APPEND LAGRAPH_STATIC_LIBS ${OpenMP_C_LIBRARIES} )
         endif ( )

ParU/CMakeLists.txt

@@ -61,7 +61,11 @@ endif ( )
 
 if ( PARU_USE_OPENMP )
     # OpenMP 4.5 or later is required
-    find_package ( OpenMP COMPONENTS C CXX GLOBAL )
+    if ( CMAKE_VERSION VERSION_LESS 3.24 )
+        find_package ( OpenMP COMPONENTS C CXX )
+    else ( )
+        find_package ( OpenMP COMPONENTS C CXX GLOBAL )
+    endif ( )
     if ( OpenMP_CXX_FOUND AND OpenMP_C_FOUND )
         set ( PARU_HAS_OPENMP ON )
         if (( OpenMP_CXX_VERSION VERSION_LESS 4.5 ) OR

SPQR/CMakeLists.txt

@@ -198,17 +198,6 @@ else ( )
     set ( SPQR_CFLAGS "" )
 endif ( )
 
-# OpenMP:
-if ( OpenMP_CXX_FOUND )
-    if ( BUILD_SHARED_LIBS )
-        target_link_libraries ( SPQR PRIVATE OpenMP::OpenMP_CXX )
-    endif ( )
-    if ( BUILD_STATIC_LIBS )
-        target_link_libraries ( SPQR_static PRIVATE OpenMP::OpenMP_CXX )
-        list ( APPEND SPQR_STATIC_LIBS ${OpenMP_CXX_LIBRARIES} )
-    endif ( )
-endif ( )
-
 # libm:
 if ( NOT WIN32 )
     if ( BUILD_SHARED_LIBS )

SuiteSparse_config/CMakeLists.txt

@@ -70,7 +70,11 @@ if ( NOT SUITESPARSE_USE_OPENMP )
     set ( SUITESPARSE_CONFIG_USE_OPENMP "OFF" CACHE STRING "" FORCE )
 endif ( )
 if ( SUITESPARSE_CONFIG_USE_OPENMP OR SUITESPARSE_USE_OPENMP )
-    find_package ( OpenMP COMPONENTS C GLOBAL )
+    if ( CMAKE_VERSION VERSION_LESS 3.24 )
+        find_package ( OpenMP COMPONENTS C )
+    else ( )
+        find_package ( OpenMP COMPONENTS C GLOBAL )
+    endif ( )
 else ( )
     # OpenMP has been disabled
     set ( OpenMP_C_FOUND OFF )