diff --git a/build-scripts/fnsince.pl b/build-scripts/fnsince.pl
new file mode 100755
index 000000000..48e4b8499
--- /dev/null
+++ b/build-scripts/fnsince.pl
@@ -0,0 +1,94 @@
+#!/usr/bin/perl -w
+
+use warnings;
+use strict;
+use File::Basename;
+
+chdir(dirname(__FILE__));
+chdir('..');
+
+my @unsorted_releases = ();
+open(PIPEFH, '-|', 'git tag -l') or die "Failed to read git release tags: $!\n";
+
+while (<PIPEFH>) {
+    chomp;
+    if (/\Arelease\-(.*?)\Z/) {
+        push @unsorted_releases, $1;
+    }
+
+}
+close(PIPEFH);
+
+#print("\n\nUNSORTED\n");
+#foreach (@unsorted_releases) {
+#    print "$_\n";
+#}
+
+my @releases = sort {
+    my @asplit = split /\./, $a;
+    my @bsplit = split /\./, $b;
+    my $rc;
+    for (my $i = 0; $i < scalar(@asplit); $i++) {
+        return 1 if (scalar(@bsplit) <= $i);  # a is "2.0.1" and b is "2.0", or whatever.
+        my $aseg = $asplit[$i];
+        my $bseg = $bsplit[$i];
+        $rc = int($aseg) <=> int($bseg);
+        return $rc if ($rc != 0);  # found the difference.
+    }
+    return 0;  # still here? They matched completely?!
+} @unsorted_releases;
+
+#print("\n\nSORTED\n");
+#foreach (@releases) {
+#    print "$_\n";
+#}
+
+push @releases, 'HEAD';
+
+my %funcs = ();
+foreach my $release (@releases) {
+    #print("Checking $release...\n");
+    next if ($release eq '2.0.0') || ($release eq '2.0.1');  # no dynapi before 2.0.2
+    my $assigned_release = ($release eq '2.0.2') ? '2.0.0' : $release;  # assume everything in 2.0.2--first with dynapi--was there since 2.0.0. We'll fix it up later.
+    my $tag = ($release eq 'HEAD') ? $release : "release-$release";
+    my $blobname = "$tag:src/dynapi/SDL_dynapi_overrides.h";
+    open(PIPEFH, '-|', "git show '$blobname'") or die "Failed to read git blob '$blobname': $!\n";
+    while (<PIPEFH>) {
+        chomp;
+        if (/\A\#define\s+(SDL_.*?)\s+SDL_.*?_REAL\Z/) {
+            my $fn = $1;
+            $funcs{$fn} = $assigned_release if not defined $funcs{$fn};
+        }
+    }
+    close(PIPEFH);
+}
+
+# Fixup the handful of functions that were added in 2.0.1 and 2.0.2 that we
+#  didn't have dynapi revision data about...
+$funcs{'SDL_GetSystemRAM'} = '2.0.1';
+$funcs{'SDL_GetBasePath'} = '2.0.1';
+$funcs{'SDL_GetPrefPath'} = '2.0.1';
+$funcs{'SDL_UpdateYUVTexture'} = '2.0.1';
+$funcs{'SDL_GL_GetDrawableSize'} = '2.0.1';
+
+$funcs{'SDL_GetAssertionHandler'} = '2.0.2';
+$funcs{'SDL_GetDefaultAssertionHandler'} = '2.0.2';
+$funcs{'SDL_AtomicAdd'} = '2.0.2';
+$funcs{'SDL_AtomicGet'} = '2.0.2';
+$funcs{'SDL_AtomicGetPtr'} = '2.0.2';
+$funcs{'SDL_AtomicSet'} = '2.0.2';
+$funcs{'SDL_AtomicSetPtr'} = '2.0.2';
+$funcs{'SDL_HasAVX'} = '2.0.2';
+$funcs{'SDL_GameControllerAddMappingsFromRW'} = '2.0.2';
+$funcs{'SDL_acos'} = '2.0.2';
+$funcs{'SDL_asin'} = '2.0.2';
+$funcs{'SDL_vsscanf'} = '2.0.2';
+$funcs{'SDL_DetachThread'} = '2.0.2';
+$funcs{'SDL_GL_ResetAttributes'} = '2.0.2';
+
+foreach my $release (@releases) {
+    foreach my $fn (sort keys %funcs) {
+        print("$fn: $funcs{$fn}\n") if $funcs{$fn} eq $release;
+    }
+}
+