bpo-35257: Avoid leaking LTO linker flags into distutils (GH-10900)

When compiling 3rd party C extensions, the linker flags used by the
compiler for the interpreter and the stdlib modules, will get
leaked into distutils. In order to avoid that, the PY_CORE_LDFLAGS
and PY_LDFLAGS_NODIST are introduced to keep those flags separated.

configure

@@ -666,6 +666,7 @@ SHLIB_SUFFIX
 LIBTOOL_CRUFT
 OTHER_LIBTOOL_OPT
 UNIVERSAL_ARCH_FLAGS
+LDFLAGS_NODIST
 CFLAGS_NODIST
 BASECFLAGS
 CFLAGS_ALIASING
@@ -6627,7 +6628,7 @@ $as_echo "$as_me: llvm-ar found via xcrun: ${LLVM_AR}" >&6;}
   fi
 
   CFLAGS_NODIST="$CFLAGS_NODIST $LTOFLAGS"
-  LDFLAGS="$LDFLAGS $LTOFLAGS"
+  LDFLAGS_NODIST="$LDFLAGS_NODIST $LTOFLAGS"
 fi
 
 # Enable PGO flags.
@@ -6879,6 +6880,7 @@ fi
 
 
 
+
 # The -arch flags for universal builds on OSX
 UNIVERSAL_ARCH_FLAGS=