mention the --static option of pkg-config

doc/chapters/basic-examples.texi

@@ -40,6 +40,8 @@ LDFLAGS         +=      $$(pkg-config --libs libstarpu)
 @end example
 @end cartouche
 
+Also pass the @code{--static} option if the application is to be linked statically.
+
 @node Hello World
 @section Hello World
 

doc/chapters/fft-support.texi

@@ -55,6 +55,8 @@ with the following commands:
 % pkg-config --libs libstarpufft    # options for the linker
 @end example
 
+Also pass the @code{--static} option if the application is to be linked statically.
+
 @subsection Initialisation
 
 @deftypefun {void *} starpufft_malloc (size_t @var{n})

doc/chapters/mpi-support.texi

@@ -42,6 +42,8 @@ accessible with the following commands:
 % pkg-config --libs libstarpumpi    # options for the linker
 @end example
 
+Also pass the @code{--static} option if the application is to be linked statically.
+
 @subsection Initialisation
 
 @deftypefun int starpu_mpi_initialize (void)

doc/chapters/using.texi

@@ -40,6 +40,8 @@ accessible with the following commands:
 % pkg-config --libs libstarpu    # options for the linker
 @end example
 
+Also pass the @code{--static} option if the application is to be linked statically.
+
 @node Running a basic StarPU application
 @section Running a basic StarPU application