Repository: bulletphysics/bullet3

Issue:
Error building on Linux
Attempting to build on Linux using g++ 4.4.7 and running the command:

```
./premake4_linux gmake
cd gmake
make config=release32
```

results in:

```
==== Building BulletInverseDynamicsUtils (release32) ====
Creating obj/x32/Release/BulletInverseDynamicsUtils
MultiBodyTreeCreator.cpp
In file included from ../../src/BulletInverseDynamics/IDConfig.hpp:65,
                 from ../../Extras/InverseDynamics/MultiBodyTreeCreator.hpp:6,
                 from ../../Extras/InverseDynamics/MultiBodyTreeCreator.cpp:1:
../../src/BulletInverseDynamics/details/IDLinearMathInterface.hpp: In constructor ‘btInverseDynamicsBullet3::vecx::vecx(int)’:
../../src/BulletInverseDynamics/details/IDLinearMathInterface.hpp:51: error: class ‘btInverseDynamicsBullet3::vecx’ does not have any field named ‘btVectorX’
../../src/BulletInverseDynamics/details/IDLinearMathInterface.hpp: In member function ‘const btInverseDynamicsBullet3::vecx& btInverseDynamicsBullet3::vecx::operator=(const btVectorX<float>&)’:
../../src/BulletInverseDynamics/details/IDLinearMathInterface.hpp:53: error: expected type-specifier before ‘btVectorX’
../../src/BulletInverseDynamics/details/IDLinearMathInterface.hpp:53: error: expected ‘>’ before ‘btVectorX’
../../src/BulletInverseDynamics/details/IDLinearMathInterface.hpp:53: error: expected ‘(’ before ‘btVectorX’
../../src/BulletInverseDynamics/details/IDLinearMathInterface.hpp:53: error: missing template arguments before ‘*’ token
../../src/BulletInverseDynamics/details/IDLinearMathInterface.hpp:53: error: expected primary-expression before ‘>’ token
../../src/BulletInverseDynamics/details/IDLinearMathInterface.hpp:53: error: expected ‘)’ before ‘;’ token
make[1]: *** [obj/x32/Release/BulletInverseDynamicsUtils/MultiBodyTreeCreator.o] Error 1
make: *** [BulletInverseDynamicsUtils] Error 2
```



Discussion:

Patch:
diff --git a/src/BulletInverseDynamics/details/IDLinearMathInterface.hpp b/src/BulletInverseDynamics/details/IDLinearMathInterface.hpp
index c77ba3cbaa..d81647b68b 100644
--- a/src/BulletInverseDynamics/details/IDLinearMathInterface.hpp
+++ b/src/BulletInverseDynamics/details/IDLinearMathInterface.hpp
@@ -48,9 +48,9 @@ inline mat33 operator*(const idScalar& s, const mat33& a) { return a * s; }
 
 class vecx : public btVectorX<idScalar> {
 public:
-	vecx(int size) : btVectorX(size) {}
+	vecx(int size) : btVectorX<idScalar>(size) {}
 	const vecx& operator=(const btVectorX<idScalar>& rhs) {
-		*static_cast<btVectorX*>(this) = rhs;
+		*static_cast<btVectorX<idScalar>*>(this) = rhs;
 		return *this;
 	}