gnu: mumble: Fix build with Boost 1.66.

Fixes <https://bugs.gnu.org/31775>.

* gnu/packages/patches/mumble-1.2.19-abs.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/telephony.scm (mumble)[source]: Add it.

1 files changed, 31 insertions, 0 deletions

diff --git a/gnu/packages/patches/mumble-1.2.19-abs.patch b/gnu/packages/patches/mumble-1.2.19-abs.patch
new file mode 100644
index 0000000000..683325f4bc
--- /dev/null
+++ b/gnu/packages/patches/mumble-1.2.19-abs.patch
@@ -0,0 +1,31 @@
+From ea861fe86743c8402bbad77d8d1dd9de8dce447e Mon Sep 17 00:00:00 2001
+From: Mikkel Krautz <mikkel@krautz.dk>
+Date: Fri, 29 Dec 2017 14:47:25 +0100
+Subject: [PATCH] AudioOutput: do not use non-existant template version of
+ std::abs.
+
+This change fixes AudioOutput to use the float overload of std::abs:
+
+    float std::abs(float);
+
+instead of a non-existant template version (for newer Boost 1.66).
+
+Fixes mumble-voip/mumble#3281
+
+---
+ src/mumble/AudioOutput.cpp | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/src/mumble/AudioOutput.cpp b/src/mumble/AudioOutput.cpp
+index cbe0c0e2b..7a0a5e2ab 100644
+--- a/src/mumble/AudioOutput.cpp
++++ b/src/mumble/AudioOutput.cpp
+@@ -437,7 +437,7 @@ bool AudioOutput::mix(void *outbuff, unsigned int nsamp) {
+ 					top[2] = 0.0f;
+ 				}
+ 
+-				if (std::abs<float>(front[0] * top[0] + front[1] * top[1] + front[2] * top[2]) > 0.01f) {
++				if (std::abs(front[0] * top[0] + front[1] * top[1] + front[2] * top[2]) > 0.01f) {
+ 					// Not perpendicular. Assume Y up and rotate 90 degrees.
+ 
+ 					float azimuth = 0.0f;