feat(config): Add -z pack-relative-relocs to LDFLAGS

This moves relative relocations from the `.rela.dyn` section into a new
`.relr.dyn` section with a significantly more compact encoding,
supported since glibc 2.36, GNU Binutils 2.38 and LLVM 15.

This can reduce the size of libraries a lot, e.g. the installed size of
`libphonenumber` dropped from about 17 MB to 7 MB.

For more info, see
https://gitlab.archlinux.org/archlinux/rfcs/-/merge_requests/23.

Signed-off-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org>

2 files changed, 4 insertions, 2 deletions

diff --git a/config/makepkg/x86_64.conf b/config/makepkg/x86_64.conf
index 9307661..e258e07 100644
--- a/config/makepkg/x86_64.conf
+++ b/config/makepkg/x86_64.conf
@@ -44,7 +44,8 @@ CFLAGS="-march=x86-64 -mtune=generic -O2 -pipe -fno-plt -fexceptions \
         -Wp,-D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security \
         -fstack-clash-protection -fcf-protection"
 CXXFLAGS="$CFLAGS -Wp,-D_GLIBCXX_ASSERTIONS"
-LDFLAGS="-Wl,-O1 -Wl,--sort-common -Wl,--as-needed -Wl,-z,relro -Wl,-z,now"
+LDFLAGS="-Wl,-O1 -Wl,--sort-common -Wl,--as-needed -Wl,-z,relro -Wl,-z,now \
+         -Wl,-z,pack-relative-relocs"
 LTOFLAGS="-flto=auto"
 RUSTFLAGS=""
 #-- Make Flags: change this for DistCC/SMP systems
diff --git a/config/makepkg/x86_64_v3.conf b/config/makepkg/x86_64_v3.conf
index 01e206d..3832b19 100644
--- a/config/makepkg/x86_64_v3.conf
+++ b/config/makepkg/x86_64_v3.conf
@@ -44,7 +44,8 @@ CFLAGS="-march=x86-64-v3 -mtune=generic -O2 -pipe -fno-plt -fexceptions \
         -Wp,-D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security \
         -fstack-clash-protection -fcf-protection"
 CXXFLAGS="$CFLAGS -Wp,-D_GLIBCXX_ASSERTIONS"
-LDFLAGS="-Wl,-O1 -Wl,--sort-common -Wl,--as-needed -Wl,-z,relro -Wl,-z,now"
+LDFLAGS="-Wl,-O1 -Wl,--sort-common -Wl,--as-needed -Wl,-z,relro -Wl,-z,now \
+         -Wl,-z,pack-relative-relocs"
 LTOFLAGS="-flto=auto"
 RUSTFLAGS=""
 #-- Make Flags: change this for DistCC/SMP systems