Bump SIMDE commit to the most up-to-date (1c68d9a)

Signed-off-by: Luis Pereira <lpereira@allbesmart.pt>

cmake_targets/tools/build_helper

@@ -494,8 +494,8 @@ install_simde_from_source(){
     if [[ -v SIMDE_VERSION ]]; then
       git checkout -f $SIMDE_VERSION
     else
-      # At time of writing, last working commit for OAI: c7f26b7
-      git checkout c7f26b73ba8e874b95c2cec2b497826ad2188f68
+      # At time of writing, last working commit for OAI: 1c68d9a
+      git checkout 1c68d9ad60bf63f3fb527c4ee3b2319d828ffcc6
     fi
     # Showing which version is used
     git log -n1

openair1/PHY/MODULATION/nr_modulation.c

@@ -7,8 +7,10 @@
 #include "PHY/NR_REFSIG/nr_mod_table.h"
 #include "executables/softmodem-common.h"
 #include <simde/x86/avx512.h>
-// Lacking declaration in present simde external package, will be detected as compilation error when they will add it
+// Lacking declaration in older implementations of simde external package, so let's keep it for now to be backwards compatible
+#if !defined(simde_mm512_extracti64x2_epi64)
 #define simde_mm512_extracti64x2_epi64(a...) _mm512_extracti64x2_epi64(a)
+#endif
 
 // #define DEBUG_DLSCH_PRECODING_PRINT_WITH_TRIVIAL // TODO: For debug, to be removed if want to merge to develop
 // #define DEBUG_LAYER_MAPPING