Patch written by Matteo Bernardini <ponce@slackbuilds.org>
Just followed the gcc hints ;)

diff -Naur FreeCAD-0.12.5284.orig/src/Mod/Mesh/App/WildMagic4/Wm4Query2Filtered.inl FreeCAD-0.12.5284/src/Mod/Mesh/App/WildMagic4/Wm4Query2Filtered.inl
--- FreeCAD-0.12.5284.orig/src/Mod/Mesh/App/WildMagic4/Wm4Query2Filtered.inl	2012-01-02 19:31:49.000000000 +0100
+++ FreeCAD-0.12.5284/src/Mod/Mesh/App/WildMagic4/Wm4Query2Filtered.inl	2012-09-12 07:01:33.501676355 +0200
@@ -55,7 +55,7 @@
     Real fLen1 = Math<Real>::Sqrt(fX1*fX1 + fY1*fY1);
     Real fScaledUncertainty = m_fUncertainty*fLen0*fLen1;
 
-    Real fDet2 = Det2(fX0,fY0,fX1,fY1);
+    Real fDet2 = this->Det2(fX0,fY0,fX1,fY1);
     if (Math<Real>::FAbs(fDet2) >= fScaledUncertainty)
     {
         return (fDet2 > (Real)0.0 ? +1 : (fDet2 < (Real)0.0 ? -1 : 0));
@@ -93,7 +93,7 @@
     Real fLen2 = Math<Real>::Sqrt(fD2x*fD2x + fD2y*fD2y + fZ2*fZ2);
     Real fScaledUncertainty = m_fUncertainty*fLen0*fLen1*fLen2;
 
-    Real fDet3 = Det3(fD0x,fD0y,fZ0,fD1x,fD1y,fZ1,fD2x,fD2y,fZ2);
+    Real fDet3 = this->Det3(fD0x,fD0y,fZ0,fD1x,fD1y,fZ1,fD2x,fD2y,fZ2);
     if (Math<Real>::FAbs(fDet3) >= fScaledUncertainty)
     {
         return (fDet3 < (Real)0.0 ? 1 : (fDet3 > (Real)0.0 ? -1 : 0));
diff -Naur FreeCAD-0.12.5284.orig/src/Mod/Mesh/App/WildMagic4/Wm4Query3Filtered.inl FreeCAD-0.12.5284/src/Mod/Mesh/App/WildMagic4/Wm4Query3Filtered.inl
--- FreeCAD-0.12.5284.orig/src/Mod/Mesh/App/WildMagic4/Wm4Query3Filtered.inl	2012-01-02 19:31:49.000000000 +0100
+++ FreeCAD-0.12.5284/src/Mod/Mesh/App/WildMagic4/Wm4Query3Filtered.inl	2012-09-12 07:03:13.704678326 +0200
@@ -62,7 +62,7 @@
     Real fLen2 = Math<Real>::Sqrt(fX2*fX2 + fY2*fY2 + fZ2*fZ2);
     Real fScaledUncertainty = m_fUncertainty*fLen0*fLen1*fLen2;
 
-    Real fDet3 = Det3(fX0,fY0,fZ0,fX1,fY1,fZ1,fX2,fY2,fZ2);
+    Real fDet3 = this->Det3(fX0,fY0,fZ0,fX1,fY1,fZ1,fX2,fY2,fZ2);
     if (Math<Real>::FAbs(fDet3) >= fScaledUncertainty)
     {
         return (fDet3 > (Real)0.0 ? +1 : (fDet3 < (Real)0.0 ? -1 : 0));
@@ -115,7 +115,7 @@
     Real fLen3 = Math<Real>::Sqrt(fD3x*fD3x+fD3y*fD3y+fD3z*fD3z+fW3*fW3);
     Real fScaledUncertainty = m_fUncertainty*fLen0*fLen1*fLen2*fLen3;
 
-    Real fDet4 = Det4(fD0x,fD0y,fD0z,fW0,fD1x,fD1y,fD1z,fW1,fD2x,
+    Real fDet4 = this->Det4(fD0x,fD0y,fD0z,fW0,fD1x,fD1y,fD1z,fW1,fD2x,
         fD2y,fD2z,fW2,fD3x,fD3y,fD3z,fW3);
 
     if (Math<Real>::FAbs(fDet4) >= fScaledUncertainty)