cmake: add page (closes #1172)

pages/common/cmake.md

@@ -0,0 +1,26 @@
+# cmake
+
+> CMake is a cross-platform build system generator.
+
+Make a project in the same directory as the source:
+
+```
+cmake
+make
+```
+
+Make a project in a subdirectory, required for some projects:
+
+```
+mkdir build
+cd build
+cmake ../
+make
+```
+
+To run cmake in interactive mode (It will ask you for each variable, 
+instead of relying on defaults):
+
+`cmake -i`
+
+