[PATCH] m4/pma.m4: disable PIE in both CFLAGS and LDFLAGS consistently

[Sergei Trofimovich]

In https://github.com/NixOS/nixpkgs/pull/207478#issuecomment-1378021841
Alyssa noticed that gawk build fails on x86_64-unknown-linux-musl target
in nixpkgs as:

    ld: .../x86_64-unknown-linux-musl/11.3.0/crtbegin.o:
        relocation R_X86_64_32 against hidden symbol `__TMC_END__'
        can not be used when making a PIE object
    ld: failed to set dynamic section sizes: bad value

This happens because both compiler (CFLAGS=-fPIE) and linker
(LDFLAGS=-pie) enable PIE by default.

As a result just disabling linker flag is not enough and `ld`
detects unresolvable dynamic relocations for non-PIE binary.

The change disables PIE for both CFLAGS and LDFLAGS.
---
 m4/pma.m4 | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/m4/pma.m4 b/m4/pma.m4
index c0535a26..73f6b316 100644
--- a/m4/pma.m4
+++ b/m4/pma.m4
@@ -19,9 +19,13 @@ then
                use_persistent_malloc=yes
                case $host_os in
                linux-*)
+                       # Guard against toolchains that default to CFLAGS=-fPIE 
LDFLAGS=-pie
                        AX_CHECK_COMPILE_FLAG([-no-pie],
                                [LDFLAGS="${LDFLAGS} -no-pie"
                                export LDFLAGS])
+                       AX_CHECK_COMPILE_FLAG([-fno-PIE],
+                               [CFLAGS="${CFLAGS} -fno-PIE"
+                               export CFLAGS])
                        ;;
                *darwin*)
                        # 27 November 2022: PMA only works on Intel.
-- 
2.38.1