0027152: Undefined symbols in library TKernel.so using clang compiler

Added ldl dependency for TKernel only (other toolkits were checked, no undefined symbols)
Added  option "-z defs" for linking on Linux
Added lm dependency for all toolkits

adm/cmake/occt_csf.cmake

@@ -77,6 +77,7 @@ else()
     set (CSF_ThreadLibs  "pthread rt stdc++")
     set (CSF_OpenGlLibs  "GLU GL")
     set (CSF_XwLibs      "X11 Xext Xmu Xi")
+    set (CSF_dl          "dl")
 
     if (USE_TCL)
       set (CSF_TclLibs     "tcl${3RDPARTY_TCL_LIBRARY_VERSION}")

adm/cmake/occt_defs_flags.cmake

@@ -92,6 +92,17 @@ if (MSVC)
   endif()
 elseif (CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra")
+  if (BUILD_SHARED_LIBS)
+    if (APPLE)
+      set (CMAKE_SHARED_LINKER_FLAGS "-lm ${CMAKE_SHARED_LINKER_FLAGS}")
+    else()
+      set (CMAKE_SHARED_LINKER_FLAGS "-lm -z defs ${CMAKE_SHARED_LINKER_FLAGS}")
+    endif()
+  else()
+    if (NOT ANDROID)
+      set (CMAKE_STATIC_LINKER_FLAGS "-lm ${CMAKE_SHARED_STATIC_FLAGS}")
+    endif()
+  endif()
 endif()
 
 if (DEFINED CMAKE_COMPILER_IS_GNUCXX OR "x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xClang")

src/TKernel/EXTERNLIB

@@ -3,3 +3,4 @@ CSF_advapi32
 CSF_gdi32
 CSF_user32
 CSF_TBB
+CSF_dl