subversion: Fix build with PERL_MM_OPT set

Without this change, the build aborts in Makefile.pl with the following
error: "Only one of PREFIX or INSTALL_BASE can be given. Not both."
PERL_MB_OPT and PERL_MM_OPT usually get set from the shell's profile, if
the user configured the CPAN shell to install modules to the users HOME.

Closes #46091.

Signed-off-by: Dominyk Tiller <dominyktiller@gmail.com>

Library/Formula/subversion.rb

@@ -75,6 +75,11 @@ def install
       inreplace "SConstruct", "unique=1", "unique=0"
 
       ENV.universal_binary if build.universal?
+
+      # Fix perl bindings Makefile.pl failing with:
+      # Only one of PREFIX or INSTALL_BASE can be given.  Not both.
+      ENV.delete "PERL_MM_OPT"
+
       # scons ignores our compiler and flags unless explicitly passed
       args = %W[PREFIX=#{serf_prefix} GSSAPI=/usr CC=#{ENV.cc}
                 CFLAGS=#{ENV.cflags} LINKFLAGS=#{ENV.ldflags}