build: Drop no longer needed -fvisibility=hidden compiler option

Author: hebasto

CMakeLists.txt

@@ -271,8 +271,6 @@ else()
   try_append_c_flags(-Wundef)
 endif()
 
-set(CMAKE_C_VISIBILITY_PRESET hidden)
-
 set(print_msan_notice)
 if(SECP256K1_BUILD_CTIME_TESTS)
   include(CheckMemorySanitizer)

configure.ac

@@ -111,7 +111,6 @@ AC_DEFUN([SECP_TRY_APPEND_DEFAULT_CFLAGS], [
       SECP_TRY_APPEND_CFLAGS([-Wcast-align=strict], $1) # GCC >= 8.0
       SECP_TRY_APPEND_CFLAGS([-Wconditional-uninitialized], $1) # Clang >= 3.0 only
       SECP_TRY_APPEND_CFLAGS([-Wreserved-identifier], $1) # Clang >= 13.0 only
-      SECP_TRY_APPEND_CFLAGS([-fvisibility=hidden], $1) # GCC >= 4.0
 
       CFLAGS="$SECP_TRY_APPEND_DEFAULT_CFLAGS_saved_CFLAGS"
     fi