Fixing compilation of the examples when PETSC is not present

build.sh

@@ -139,6 +139,7 @@ else
  if [ x"$comp_type" == x"full" ]; then
   echo "Installing with: ./install -i $HOME/openfpm_dependencies/openfpm_pdata/$branch  -s -c \"$installation_dir\"  "
   ./install -i $HOME/openfpm_dependencies/openfpm_pdata/$branch  -s -c "$installation_dir"
+  make install
   if [ $? -ne 0 ]; then
     curl -X POST --data "payload={\"icon_emoji\": \":jenkins:\", \"username\": \"jenkins\"  , \"attachments\":[{ \"title\":\"Error:\", \"color\": \"#FF0000\", \"text\":\"$hostname failed to complete the openfpm_pdata test \" }] }" https://hooks.slack.com/services/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
     exit 1 ;

example/Numerics/Stoke_flow/0_2D_incompressible/main_petsc.cpp

@@ -30,6 +30,10 @@
 
 //! \cond [def system] \endcond
 
+#include "config.h"
+
+#ifdef HAVE_PETSC
+
 #include "Grid/grid_dist_id.hpp"
 #include "Matrix/SparseMatrix.hpp"
 #include "Vector/Vector.hpp"
@@ -441,3 +445,12 @@ int main(int argc, char* argv[])
 	 */
 }
 
+
+#else
+
+int main(int argc, char* argv[])
+{
+        return 0;
+}
+
+#endif

example/Numerics/Stoke_flow/1_3D_incompressible/main_petsc.cpp

@@ -31,6 +31,10 @@
 
 //! \cond [def system] \endcond
 
+#include "config.h"
+
+#ifdef HAVE_PETSC
+
 #include "Grid/grid_dist_id.hpp"
 #include "Matrix/SparseMatrix.hpp"
 #include "Vector/Vector.hpp"
@@ -502,3 +506,12 @@ int main(int argc, char* argv[])
 	 *
 	 */
 }
+
+#else
+
+int main(int argc, char* argv[])
+{
+        return 0;
+}
+
+#endif