Fix compilation errors with libc++ on QNX 7upstream/qnx_erros

This patch fixes the compilation errors on QNX 7:
1) It seems that the QNX 7 compiler (i.e qcc based GCC 5.4.0 with libc++
from LLVM) has a limited c++11 feature support and causing the compilation
errors with the inheriting constructors. Fix the issues by providing the
required constructors explicitly.

2) Resolve an ambiguous overload error with optional<T>

3) Remove use of noncopyable in Context

1 files changed, 6 insertions, 6 deletions

diff --git a/src/mbgl/style/expression/interpolate.cpp b/src/mbgl/style/expression/interpolate.cpp
index a9bb3bf05e..31fd360fa9 100644
--- a/src/mbgl/style/expression/interpolate.cpp
+++ b/src/mbgl/style/expression/interpolate.cpp
@@ -170,23 +170,23 @@ ParseResult parseInterpolate(const Convertible& value, ParsingContext& ctx) {
             labelValue->match(
                 [&](uint64_t n) {
                     if (n > std::numeric_limits<double>::max()) {
-                        label = {std::numeric_limits<double>::infinity()};
+                        label = optional<double>{std::numeric_limits<double>::infinity()};
                     } else {
-                        label = {static_cast<double>(n)};
+                        label = optional<double>{static_cast<double>(n)};
                     }
                 },
                 [&](int64_t n) {
                     if (n > std::numeric_limits<double>::max()) {
-                        label = {std::numeric_limits<double>::infinity()};
+                        label = optional<double>{std::numeric_limits<double>::infinity()};
                     } else {
-                        label = {static_cast<double>(n)};
+                        label = optional<double>{static_cast<double>(n)};
                     }
                 },
                 [&](double n) {
                     if (n > std::numeric_limits<double>::max()) {
-                        label = {std::numeric_limits<double>::infinity()};
+                        label = optional<double>{std::numeric_limits<double>::infinity()};
                     } else {
-                        label = {static_cast<double>(n)};
+                        label = optional<double>{n};
                     }
                 },
                 [&](const auto&) {}