Fixing ICPC usage with modern cmake and wrappers

Related to conan's conan-io/conan-center-index#25843

replaced 'fp-model strict' by 'fp-model=strict' https://www.intel.com/content/www/us/en/docs/cpp-compiler/developer-guide-reference/2021-8/fp-model-fp.html
for more compatibility with nvcc. as 'fp-model=strict' will be directly
transmited to the compiler while 'fp-model strict' will have 'strict'
being treated as a file input.

Also added a CXX only filter for newer cmake 3.3+

Author: mbarbier

Installation/CMakeLists.txt

@@ -433,12 +433,12 @@ if("${CMAKE_CXX_COMPILER}" MATCHES "icl" OR "${CMAKE_CXX_COMPILER}" MATCHES
     )
   else()
     message(
-      STATUS "Using Intel Compiler version 11 or later. Adding -fp-model strict"
+      STATUS "Using Intel Compiler version 11 or later. Adding -fp-model=strict"
     )
     if(WIN32)
       uniquely_add_flags(CGAL_CXX_FLAGS "/fp:strict")
     else()
-      uniquely_add_flags(CGAL_CXX_FLAGS "-fp-model strict")
+      uniquely_add_flags(CGAL_CXX_FLAGS "-fp-model=strict")
     endif()
   endif()
 endif()

Installation/cmake/modules/CGAL_SetupCGALDependencies.cmake

@@ -132,11 +132,19 @@ function(CGAL_setup_CGAL_flags target)
       $<$<COMPILE_LANGUAGE:CXX>:/bigobj>  # Use /bigobj by default
       )
   elseif(CMAKE_CXX_COMPILER_ID MATCHES "Intel")
-    message( STATUS "Using Intel Compiler. Adding -fp-model strict" )
-    if(WIN32)
-      target_compile_options(${target} INTERFACE "/fp:strict")
+    # cuda knows how to deal with 'fp-model=strict' but not 'fp-model strict'
+    if(CMAKE_VERSION VERSION_LESS 3.3)
+      if(WIN32)
+        target_compile_options(${target} INTERFACE "/fp:strict")
+      else()
+        target_compile_options(${target} INTERFACE "-fp-model=strict")
+      endif()
     else()
-      target_compile_options(${target} INTERFACE "-fp-model" "strict")
+      if(WIN32)
+        target_compile_options(${target} INTERFACE "$<$<COMPILE_LANGUAGE:CXX>:/fp:strict>")
+      else()
+        target_compile_options(${target} INTERFACE "$<$<COMPILE_LANGUAGE:CXX>:-fp-model=strict>")
+      endif()
     endif()
   elseif(CMAKE_CXX_COMPILER_ID MATCHES "SunPro")
     message( STATUS "Using SunPro compiler, using STLPort 4." )

Number_types/include/CGAL/Interval_nt.h

@@ -285,9 +285,9 @@ class Interval_nt
       // the 2 negations and we get wrong rounding.
       typename Interval_nt<>::Internal_protector P;
       CGAL_assertion_msg(-CGAL_IA_MUL(-1.1, 10.1) != CGAL_IA_MUL(1.1, 10.1),
-                         "Wrong rounding: did you forget the  -frounding-math  option if you use GCC (or  -fp-model strict  for Intel)?");
+                         "Wrong rounding: did you forget the  -frounding-math  option if you use GCC (or  -fp-model=strict  for Intel)?");
       CGAL_assertion_msg(-CGAL_IA_DIV(-1., 10) != CGAL_IA_DIV(1., 10),
-                         "Wrong rounding: did you forget the  -frounding-math  option if you use GCC (or  -fp-model strict  for Intel)?");
+                         "Wrong rounding: did you forget the  -frounding-math  option if you use GCC (or  -fp-model=strict  for Intel)?");
     }
   };