https://bugs.gentoo.org/show_bug.cgi?id=620732

Fixes build failure on gcc-7:

  htapp.cc: In function 'uint isqr(uint)':
  htapp.cc:3026:18: error: call of overloaded 'abs(uint)' is ambiguous
    while (abs(a - b) > 1) {
                    ^

Picked upstream patch that fixes it:

commit 3b62f2f7e49e024ec9d3c5ffc8ff9cd87a107af6
Author: Sebastian Biallas <sb@biallas.net>
Date:   Sun Nov 13 15:25:26 2016 +0100

    use unsigned variables

diff --git a/htapp.cc b/htapp.cc
index 53d8725..03236e2 100644
--- a/htapp.cc
+++ b/htapp.cc
@@ -3021,8 +3021,8 @@ void do_modal_resize()
 
 static uint isqr(uint u)
 {
-	uint a = 2;
-	uint b = u/a;
+	int a = 2;
+	int b = u/a;
 	while (abs(a - b) > 1) {
 		a = (a+b)/2;
 		b = u/a;