cmake,MKL: add default library search paths

- /opt/intel/oneapi/mkl/latest (intel-oneapi-mkl 2022.0.2)
- /opt/intel/mkl (intel-mkl 2020.4.304 on Archlinux)

cmake/modules/FindMKL.cmake

@@ -16,31 +16,45 @@
 find_path(MKL_INCLUDE_DIR
             NAMES mkl.h
             HINTS $ENV{MKL_DIR}/include
+                  /opt/intel/oneapi/mkl/latest/include
+                  /opt/intel/mkl/include
+                  /usr/include/mkl
             PATHS)
 
 find_path(MKL_FFTW_INCLUDE_DIR
             NAMES fftw3.h
             HINTS $ENV{MKL_DIR}/include/fftw
+                  /opt/intel/oneapi/mkl/latest/include/fftw
+                  /opt/intel/mkl/include/fftw
+                  /usr/include/mkl/fftw
             PATHS)
 
 find_library(MKL_LIBRARIES
             NAMES mkl_rt
             HINTS $ENV{MKL_DIR}/lib/intel64
+                  /opt/intel/oneapi/mkl/latest/lib/intel64
+                  /opt/intel/mkl/lib/intel64
             PATHS)
 
 find_library(MKL_CORE
             NAMES libmkl_core.a
             HINTS $ENV{MKL_DIR}/lib/intel64
+                  /opt/intel/oneapi/mkl/latest/lib/intel64/
+                  /opt/intel/mkl/lib/intel64
             PATHS)
 
 find_library(MKL_ILP
             NAMES libmkl_intel_ilp64.a
             HINTS $ENV{MKL_DIR}/lib/intel64
+                  /opt/intel/oneapi/mkl/latest/lib/intel64/
+                  /opt/intel/mkl/lib/intel64
             PATHS)
 
 find_library(MKL_SEQ
             NAMES libmkl_sequential.a
             HINTS $ENV{MKL_DIR}/lib/intel64
+                  /opt/intel/oneapi/mkl/latest/lib/intel64/
+                  /opt/intel/mkl/lib/intel64
             PATHS)
 
 set(MKL_STATIC_LIBRARIES -Wl,--start-group ${MKL_CORE} ${MKL_ILP} ${MKL_SEQ} -Wl,--end-group -lpthread -lm -ldl)