Reintroducing libgeometry, obsolete register type (#736)

Signed-off-by: Álvaro Jurado <elbingmiss@gmail.com>

sys/src/libgeometry/matrix.c

@@ -28,7 +28,7 @@ void ident(Matrix m){
 	*s++=0;*s++=0;*s++=0;*s=1;
 }
 void matmul(Matrix a, Matrix b){
-	register i, j, k;
+	int32_t i, j, k;
 	double sum;
 	Matrix tmp;
 	for(i=0;i!=4;i++) for(j=0;j!=4;j++){
@@ -41,7 +41,7 @@ void matmul(Matrix a, Matrix b){
 		a[i][j]=tmp[i][j];
 }
 void matmulr(Matrix a, Matrix b){
-	register i, j, k;
+	int32_t i, j, k;
 	double sum;
 	Matrix tmp;
 	for(i=0;i!=4;i++) for(j=0;j!=4;j++){

sys/src/libgeometry/tstack.c

@@ -49,7 +49,7 @@ Space *popmat(Space *t){
 void rot(Space *t, double theta, int axis){
 	double s=sin(radians(theta)), c=cos(radians(theta));
 	Matrix m, inv;
-	register i=(axis+1)%3, j=(axis+2)%3;
+	int32_t i=(axis+1)%3, j=(axis+2)%3;
 	ident(m);
 	m[i][i] = c;
 	m[i][j] = -s;