Use C++ <cmath> instead of <math.h>

Including math.h can pollute the default namespace, and break
some compilers if cmath versions of the method are declared as using.

Switching to C++ math functions also greatly simplifies handling of
float qreal as C++ automatically chooses the right method.

[ChangeLog][QtCore][QtMath] qmath.h no longer includes math.h, so any
sources depending on that indirect inclusion may fail to build.

Change-Id: I4d0e331dafba354ec05dc5052e61ef4ff8d387fe
Reviewed-by: Rafael Roquetto <rafael.roquetto@kdab.com>

2 files changed, 4 insertions, 4 deletions

diff --git a/src/gui/util/qgridlayoutengine.cpp b/src/gui/util/qgridlayoutengine.cpp
index 5b98001b38..df8dab2903 100644
--- a/src/gui/util/qgridlayoutengine.cpp
+++ b/src/gui/util/qgridlayoutengine.cpp
@@ -193,7 +193,7 @@ namespace {
 // does not return int
 static inline qreal qround(qreal f)
 {
-    return floor(f + 0.5);
+    return std::floor(f + qreal(0.5));
 }
 
 }
@@ -355,7 +355,7 @@ void QGridLayoutRowData::calculateGeometries(int start, int end, qreal targetSiz
                     qreal maxBoxSize = box.q_maximumSize;
 
                     if (snapToPixelGrid)
-                        maxBoxSize = qMax(box.q_minimumSize, floor(maxBoxSize));
+                        maxBoxSize = qMax(box.q_minimumSize, std::floor(maxBoxSize));
 
                     qreal avail = sumCurrentAvailable * factors[i] / sumFactors;
                     if (sizes[i] + avail >= maxBoxSize) {
diff --git a/src/gui/util/qvalidator.cpp b/src/gui/util/qvalidator.cpp
index dcb1f9817f..6b1e20c844 100644
--- a/src/gui/util/qvalidator.cpp
+++ b/src/gui/util/qvalidator.cpp
@@ -40,7 +40,7 @@
 #include "private/qlocale_p.h"
 
 #include <limits.h>
-#include <math.h>
+#include <cmath>
 
 QT_BEGIN_NAMESPACE
 
@@ -384,7 +384,7 @@ static int numDigits(qlonglong n)
 {
     if (n == 0)
         return 1;
-    return (int)log10(double(n)) + 1;
+    return (int)std::log10(double(n)) + 1;
 }
 
 static qlonglong pow10(int exp)