Build system nonsense to fix building against an installed Qt

src/rhi/qrhi.cpp

@@ -1413,6 +1413,9 @@ QRhiTexture::QRhiTexture(QRhiImplementation *rhi, Format format_, const QSize &p
     \return a pointer to a backend-specific QRhiNativeHandles subclass, such as
     QRhiVulkanTextureNativeHandles. The returned value is null when exposing
     the underlying native resources is not supported by the backend.
+
+    \sa QRhiVulkanTextureNativeHandles, QRhiD3D11TextureNativeHandles,
+    QRhiMetalTextureNativeHandles, QRhiGles2TextureNativeHandles
  */
 const QRhiNativeHandles *QRhiTexture::nativeHandles()
 {
@@ -1423,15 +1426,24 @@ const QRhiNativeHandles *QRhiTexture::nativeHandles()
     Similar to build() except that no new native textures are created. Instead,
     the texture from \a src is used.
 
-    // Calling this instead of build() allows importing an existing native
-    // texture object (must belong to the same device or a sharing context).
-    // Note that format, pixelSize, etc. must still be set correctly (typically
-    // via QRhi::newTexture()). Ownership of the native resource is not taken.
+    This allows importing an existing native texture object (which must belong
+    to the same device or sharing context, depending on the graphics API) from
+    an external graphics engine.
+
+    \note format(), pixelSize(), sampleCount(), and flags() must still be set
+    correctly. Passing incorrect sizes and other values to QRhi::newTexture()
+    and then following it with a buildFrom() expecting that the native texture
+    object alone is sufficient to deduce such values is \b wrong and will lead
+    to problems.
 
     \note QRhiTexture does not take ownership of the texture object. release()
     does not free the object or any associated memory.
 
-    \sa QRhiVulkanTextureNativeHandles
+    The opposite of this operation, exposing a QRhiTexture-created native
+    texture object to a foreign engine, is possible via nativeHandles().
+
+    \sa QRhiVulkanTextureNativeHandles, QRhiD3D11TextureNativeHandles,
+    QRhiMetalTextureNativeHandles, QRhiGles2TextureNativeHandles
  */
 bool QRhiTexture::buildFrom(const QRhiNativeHandles *src)
 {

src/shadertools/shadertools.pro

@@ -27,9 +27,15 @@ INCLUDEPATH += $$PWD/../3rdparty/SPIRV-Cross $$PWD/../3rdparty/glslang
 # They will not propagate outside of this module though so should be safe enough.
 CONFIG += exceptions
 
+!exists($$[QT_HOST_DATA]/.qmake.cache) {
+    LIBLOC = $$shadowed($$dirname(_QMAKE_CONF_))/lib
+} else {
+    LIBLOC = $$[QT_HOST_LIBS]
+}
+
 STATICLIBS = qtspirv-cross qtglslang-glslang qtglslang-spirv qtglslang-osdependent qtglslang-oglcompiler # qtglslang-hlsl
 for(libname, STATICLIBS) {
-    staticlib = $$[QT_HOST_LIBS]/$${QMAKE_PREFIX_STATICLIB}$$qtLibraryTarget($$libname).$${QMAKE_EXTENSION_STATICLIB}
+    staticlib = $$LIBLOC/$${QMAKE_PREFIX_STATICLIB}$$qtLibraryTarget($$libname).$${QMAKE_EXTENSION_STATICLIB}
     LIBS_PRIVATE += $$staticlib
     PRE_TARGETDEPS += $$staticlib
 }