Compile with latest compilers (gcc 12, clang 15)

[gonsolo]

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c67a6b0..98e3db2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -20,7 +20,7 @@ endif (POLICY CMP0048)

 project(optix7course VERSION 1.0.1)

-cmake_minimum_required(VERSION 2.8)
+cmake_minimum_required(VERSION 3.25)
 if (NOT WIN32)
 # visual studio doesn't like these (not need them):
 set (CMAKE_CXX_FLAGS "--std=c++11")
diff --git a/common/gdt/gdt/gdt.h b/common/gdt/gdt/gdt.h
index b4eaa48..c3a5845 100644
--- a/common/gdt/gdt/gdt.h
+++ b/common/gdt/gdt/gdt.h
@@ -126,7 +126,7 @@ namespace gdt {
   // inline __both__ float cos(float f) { return ::cosf(f); }
   // inline __both__ double cos(double f) { return ::cos(f); }

-  using ::saturate;
+  //using ::saturate;
 #else
   using std::min;
   using std::max;
diff --git a/example07_firstRealModel/Model.cpp b/example07_firstRealModel/Model.cpp
index bb14939..f5114e9 100644
--- a/example07_firstRealModel/Model.cpp
+++ b/example07_firstRealModel/Model.cpp
@@ -20,7 +20,7 @@
 //std
 #include <set>

-namespace std {
+namespace tinyobj {
   inline bool operator<(const tinyobj::index_t &a,
                         const tinyobj::index_t &b)
   {
diff --git a/example08_addingTextures/Model.cpp b/example08_addingTextures/Model.cpp
index 8452638..e623a48 100644
--- a/example08_addingTextures/Model.cpp
+++ b/example08_addingTextures/Model.cpp
@@ -24,7 +24,7 @@
 //std
 #include <set>

-namespace std {
+namespace tinyobj {
   inline bool operator<(const tinyobj::index_t &a,
                         const tinyobj::index_t &b)
   {
diff --git a/example09_shadowRays/Model.cpp b/example09_shadowRays/Model.cpp
index 8452638..e623a48 100644
--- a/example09_shadowRays/Model.cpp
+++ b/example09_shadowRays/Model.cpp
@@ -24,7 +24,7 @@
 //std
 #include <set>

-namespace std {
+namespace tinyobj {
   inline bool operator<(const tinyobj::index_t &a,
                         const tinyobj::index_t &b)
   {
diff --git a/example10_softShadows/Model.cpp b/example10_softShadows/Model.cpp
index 0579863..cc4fd57 100644
--- a/example10_softShadows/Model.cpp
+++ b/example10_softShadows/Model.cpp
@@ -24,7 +24,7 @@
 //std
 #include <set>

-namespace std {
+namespace tinyobj {
   inline bool operator<(const tinyobj::index_t &a,
                         const tinyobj::index_t &b)
   {
diff --git a/example11_denoiseColorOnly/Model.cpp b/example11_denoiseColorOnly/Model.cpp
index 0579863..cc4fd57 100644
--- a/example11_denoiseColorOnly/Model.cpp
+++ b/example11_denoiseColorOnly/Model.cpp
@@ -24,7 +24,7 @@
 //std
 #include <set>

-namespace std {
+namespace tinyobj {
   inline bool operator<(const tinyobj::index_t &a,
                         const tinyobj::index_t &b)
   {
diff --git a/example12_denoiseSeparateChannels/Model.cpp b/example12_denoiseSeparateChannels/Model.cpp
index 0579863..cc4fd57 100644
--- a/example12_denoiseSeparateChannels/Model.cpp
+++ b/example12_denoiseSeparateChannels/Model.cpp
@@ -24,7 +24,7 @@
 //std
 #include <set>

-namespace std {
+namespace tinyobj {
   inline bool operator<(const tinyobj::index_t &a,
                         const tinyobj::index_t &b)
   {