add libs z, m and rt for scotch function test only if discovered on the system

cmake_modules/morse/find/FindPTSCOTCH.cmake

@@ -264,10 +264,21 @@ if(PTSCOTCH_LIBRARIES)
     if(CMAKE_THREAD_LIBS_INIT)
         list(APPEND REQUIRED_LIBS "${CMAKE_THREAD_LIBS_INIT}")
     endif()
-    if(UNIX OR WIN32)
+    set(Z_LIBRARY "Z_LIBRARY-NOTFOUND")
+    find_library(Z_LIBRARY NAMES z)
+    if(Z_LIBRARY)
+        list(APPEND REQUIRED_LIBS "-lz")
+    endif()
+    set(M_LIBRARY "M_LIBRARY-NOTFOUND")
+    find_library(M_LIBRARY NAMES m)
+    if(M_LIBRARY)
         list(APPEND REQUIRED_LIBS "-lm")
     endif()
-    list(APPEND REQUIRED_LIBS "-lz -lrt")
+    set(RT_LIBRARY "RT_LIBRARY-NOTFOUND")
+    find_library(RT_LIBRARY NAMES rt)
+    if(RT_LIBRARY)
+        list(APPEND REQUIRED_LIBS "-lrt")
+    endif()
 
     # set required libraries for link
     set(CMAKE_REQUIRED_INCLUDES "${REQUIRED_INCDIRS}")

cmake_modules/morse/find/FindSCOTCH.cmake

@@ -233,10 +233,21 @@ if(SCOTCH_LIBRARIES)
     if(CMAKE_THREAD_LIBS_INIT)
         list(APPEND REQUIRED_LIBS "${CMAKE_THREAD_LIBS_INIT}")
     endif()
-    if(UNIX OR WIN32)
+    set(Z_LIBRARY "Z_LIBRARY-NOTFOUND")
+    find_library(Z_LIBRARY NAMES z)
+    if(Z_LIBRARY)
+        list(APPEND REQUIRED_LIBS "-lz")
+    endif()
+    set(M_LIBRARY "M_LIBRARY-NOTFOUND")
+    find_library(M_LIBRARY NAMES m)
+    if(M_LIBRARY)
         list(APPEND REQUIRED_LIBS "-lm")
     endif()
-    list(APPEND REQUIRED_LIBS "-lz -lrt")
+    set(RT_LIBRARY "RT_LIBRARY-NOTFOUND")
+    find_library(RT_LIBRARY NAMES rt)
+    if(RT_LIBRARY)
+        list(APPEND REQUIRED_LIBS "-lrt")
+    endif()
 
     # set required libraries for link
     set(CMAKE_REQUIRED_INCLUDES "${REQUIRED_INCDIRS}")