https://bugs.gentoo.org/837875

/var/tmp/portage/app-text/texlive-core-2021-r1/work/texlive-20210325-source/texk/web2c/mplibdir/pngout.w:63:10: fatal error: mplib.h: No such file or directory
   63 | #include "mplib.h"
      |          ^~~~~~~~~

--- texlive-20230311-source/texk/web2c/mplibdir/am/libmplib.am
+++ texlive-20230311-source/texk/web2c/mplibdir/am/libmplib.am
@@ -24,14 +24,14 @@
 
 
 mp_c_h =  mp.c mplib.h mpmp.h
-mpmath_c_h = mpmath.h mpmath.c
-mpmathbinary_c_h = mpmathbinary.h mpmathbinary.c
-mpmathdecimal_c_h = mpmathdecimal.h mpmathdecimal.c
-mpmathdouble_c_h = mpmathdouble.h mpmathdouble.c
-mpstrings_c_h = mpstrings.h mpstrings.c
-psout_c_h = mplibps.h mppsout.h psout.c
-svgout_c_h = mplibsvg.h mpsvgout.h svgout.c
-pngout_c_h = mplibpng.h mppngout.h pngout.c
+mpmath_c_h = mpmath.h mpmath.c mplib.h
+mpmathbinary_c_h = mpmathbinary.h mpmathbinary.c mplib.h
+mpmathdecimal_c_h = mpmathdecimal.h mpmathdecimal.c mplib.h
+mpmathdouble_c_h = mpmathdouble.h mpmathdouble.c mplib.h
+mpstrings_c_h = mpstrings.h mpstrings.c mplib.h
+psout_c_h = mplibps.h mppsout.h psout.c mplib.h
+svgout_c_h = mplibsvg.h mpsvgout.h svgout.c mplib.h
+pngout_c_h = mplibpng.h mppngout.h pngout.c mplib.h
 
 # Creating one file: just one rule
 tfmin.c: ctangle$(EXEEXT) mplibdir/tfmin.w