fix: disable PIE for post_process with LLVMFlang to fix R_X86_64_32 relocation error

flang-23/LLD defaults to building PIE executables. SILO and LAPACK static
libraries on Frontier are compiled without -fPIC, so their 32-bit absolute
relocations (R_X86_64_32) are rejected by LLD when linking a PIE binary.
Add -no-pie to post_process link options for LLVMFlang to allow non-PIC
system libraries. simulation is unaffected (no SILO/LAPACK dependency).

Author: sbryngelson

CMakeLists.txt

@@ -791,6 +791,12 @@ if (MFC_POST_PROCESS)
 
     # -O0 is in response to https://github.com/MFlowCode/MFC-develop/issues/95
     target_compile_options(post_process PRIVATE -O0)
+
+    # flang-23/LLD defaults to PIE; SILO and LAPACK static libs on Frontier are
+    # non-PIC, producing R_X86_64_32 relocations that LLD rejects in PIE mode.
+    if (CMAKE_Fortran_COMPILER_ID STREQUAL "LLVMFlang")
+        target_link_options(post_process PRIVATE -no-pie)
+    endif()
 endif()
 
 if (MFC_SYSCHECK)