Rollup merge of rust-lang#133543 - mustartt:aix-lgammaf_r-shim, r=cuviper

[AIX] create shim for lgammaf_r

On AIX, we don't have 32bit floating point for re-entrant `lgammaf_r` but we do have the 64bit floating point re-entrant `lgamma_r` so we can use the 64bit version instead and truncate back to a 32bit float.

This solves the linker missing symbol for `.lgammaf_r` when testing and using these parts of the `std`.

Author: GuillaumeGomez

library/std/src/sys/cmath.rs

@@ -26,6 +26,7 @@ extern "C" {
     pub fn tgamma(n: f64) -> f64;
     pub fn tgammaf(n: f32) -> f32;
     pub fn lgamma_r(n: f64, s: &mut i32) -> f64;
+    #[cfg(not(target_os = "aix"))]
     pub fn lgammaf_r(n: f32, s: &mut i32) -> f32;
 
     pub fn acosf128(n: f128) -> f128;
@@ -56,6 +57,13 @@ extern "C" {
     }}
 }
 
+// On AIX, we don't have lgammaf_r only the f64 version, so we can
+// use the f64 version lgamma_r
+#[cfg(target_os = "aix")]
+pub unsafe fn lgammaf_r(n: f32, s: &mut i32) -> f32 {
+    lgamma_r(n.into(), s) as f32
+}
+
 // On 32-bit x86 MSVC these functions aren't defined, so we just define shims
 // which promote everything to f64, perform the calculation, and then demote
 // back to f32. While not precisely correct should be "correct enough" for now.