Merge branch 'shader_line_numbering' into 'master'

Correctly resetting line numbering during shader processing.

See merge request OpenMW/openmw!317

apps/openmw_test_suite/shader/shadermanager.cpp

@@ -92,7 +92,7 @@ namespace
                         "\n"
                         "void bar() { foo() }\n"
                         "\n"
-                        "#line 2 0\n"
+                        "#line 1 0\n"
                         "\n"
                         "void main() { bar() }\n";
                     EXPECT_EQ(shader->getShaderSource(), expected);

components/shader/shadermanager.cpp

@@ -106,7 +106,7 @@ namespace Shader
             else
             {
                 lineDirectivePosition = 0;
-                lineNumber = 1;
+                lineNumber = 0;
             }
             lineNumber += std::count(source.begin() + lineDirectivePosition, source.begin() + foundPos, '\n');