Keep playback audio compatible with the Android voice build

src/Makefile.am

@@ -1,7 +1,8 @@
 bin_PROGRAMS = utun
 noinst_LIBRARIES = libutun.a
 
-EXTRA_DIST = lwip_tcp/COPYING dnsmasq/COPYING dnsmasq/COPYING-v3 routing_layer/address_profile.h routing_layer/route_ping_doc.md
+EXTRA_DIST = lwip_tcp/COPYING dnsmasq/COPYING dnsmasq/COPYING-v3 routing_layer/address_profile.h routing_layer/route_ping_doc.md \
+    stream/stream_playback_audio.h stream/stream_playback_audio.cpp
 
 stream_core_files = \
 	stream/stream.h \

src/stream/stream_playback_audio.cpp

@@ -13,10 +13,14 @@ extern "C" {
 
 namespace {
 constexpr unsigned rate = 48000, framesPerPacket = 960, maxFrames = 8192, mapCapacity = 1024;
-struct Span { double first = 0, last = 0, ptsFirst = 0, ptsLast = 0; };
+struct Span {
+    double first, last, ptsFirst, ptsLast;
+    Span(double begin = 0, double end = 0, double ptsBegin = 0, double ptsEnd = 0)
+        : first(begin), last(end), ptsFirst(ptsBegin), ptsLast(ptsEnd) {}
+};
 double mapped(const Span& span, double position) {
     if (span.last <= span.first) return span.ptsLast;
-    double fraction = std::clamp((position - span.first) / (span.last - span.first), 0.0, 1.0);
+    double fraction = std::max(0.0, std::min(1.0, (position - span.first) / (span.last - span.first)));
     return span.ptsFirst + fraction * (span.ptsLast - span.ptsFirst);
 }
 }
@@ -156,7 +160,8 @@ int stream_playback_audio_pull(struct stream_playback_audio* a, int16_t* pcm, un
     frames = std::min(frames, std::min(available, a->stretch.numSamples()));
     if (!frames) return 0;
     unsigned got = a->stretch.receiveSamples(a->samples, frames);
-    for (unsigned i = 0; i < got * 2; i++) pcm[i] = (int16_t)std::lrint(std::clamp(a->samples[i] * 32767.0f, -32768.0f, 32767.0f));
+    for (unsigned i = 0; i < got * 2; i++)
+        pcm[i] = (int16_t)std::lrint(std::max(-32768.0f, std::min(32767.0f, a->samples[i] * 32767.0f)));
     double position = a->producedOutput, end = position + got;
     for (unsigned i = 0; i < a->inputCount && position < end; i++) {
         const auto& span = a->input[(a->inputHead + i) % mapCapacity];