Ensure Configure.pl uses gmake for builds on BSDs

Configure.pl

@@ -17,6 +17,7 @@
 my $lclang = lc $lang;
 my $uclang = uc $lang;
 my $win    = $^O eq 'MSWin32';
+my $unix   = is_OS_type_Unix();
 my $slash  = $win ? '\\' : '/';
 # We don't use ExtUtils::Command in Configure.pl, but it is used in the Makefile
 # Try `use`ing it here so users know if they need to install this module
@@ -148,11 +149,13 @@
     $config{'runner_suffix'} = $win ? '.bat' : '';
 
     my $make = 'make';
-    if ($^O eq 'solaris') {
-        if (not -X '/usr/bin/gmake') {
-            die "gmake is required to compile rakudo. Please install by 'pkg install gnu-make'";
+    if ($unix) {
+        my $has_make = 0 == system('make --version >/dev/null 2>&1');
+        unless ($has_make) {
+            my $has_gmake = 0 == system('gmake --version >/dev/null 2>&1');
+            die "gmake is required to compile rakudo. Please install it with your operating system's package manager or from source." unless $has_gmake;
+            $make = 'gmake';
         }
-        $make = 'gmake';
     }
 
     if ($win) {
@@ -189,7 +192,7 @@
 
     print $MAKEFILE "\n# Makefile code generated by Configure.pl:\n";
 
-    if ( is_OS_type_Unix() ) {
+    if ($unix) {
         $config{mkpath} = 'mkdir -p --';
         $config{chmod}  = 'chmod --';
         $config{cp}     = 'cp --';