mention libhwloc instead of just hwloc, to increase probability of the user figuring out that the hwloc tools are not enough

configure.ac

@@ -2495,7 +2495,7 @@ AS_IF([test "$use_hwloc" = "yes" -a "$have_valid_hwloc" = "no"],
      )
 # in case hwloc is not available but was not explicitely disabled, this is an error
 AS_IF([test "$have_valid_hwloc" = "no" -a "$use_hwloc" != "no"],
-      [AC_MSG_ERROR([hwloc was not found on your system. If the target machine is hyperthreaded the performance may be impacted a lot.  It is strongly recommended to install hwloc. However, if you really want to use StarPU without enabling hwloc, please restart configure by specifying the option '--without-hwloc'.])]
+      [AC_MSG_ERROR([libhwloc was not found on your system. If the target machine is hyperthreaded the performance may be impacted a lot.  It is strongly recommended to install libhwloc. However, if you really want to use StarPU without enabling libhwloc, please restart configure by specifying the option '--without-hwloc'.])]
      )
 
 AS_IF([test "$have_valid_hwloc" = "yes"],

doc/doxygen/chapters/01building.doxy

@@ -35,12 +35,12 @@ can be used to install StarPU.
 The <c>hwloc</c> (http://www.open-mpi.org/software/hwloc) topology
 discovery library is not mandatory to use StarPU but strongly
 recommended.  It allows for topology aware scheduling, which improves
-performance.  <c>hwloc</c> is available in major free operating system
+performance.  <c>libhwloc</c> is available in major free operating system
 distributions, and for most operating systems.
 
-If <c>hwloc</c> is not available on your system, the option
+If <c>libhwloc</c> is not available on your system, the option
 \ref without-hwloc "--without-hwloc" should be explicitely given when calling the
-<c>configure</c> script. If <c>hwloc</c> is installed with a <c>pkg-config</c> file,
+<c>configure</c> script. If <c>libhwloc</c> is installed with a <c>pkg-config</c> file,
 no option is required, it will be detected automatically, otherwise
 \ref with-hwloc "--with-hwloc" should be used to specify its location.
 
@@ -218,7 +218,7 @@ When StarPU is used for the first time, the directory
 that directory (\ref STARPU_HOME).
 
 Please note that buses are benchmarked when StarPU is launched for the
-first time. This may take a few minutes, or less if <c>hwloc</c> is
+first time. This may take a few minutes, or less if <c>libhwloc</c> is
 installed. This step is done only once per user and per machine.
 
 \subsection RunningABasicStarPUApplicationOnMicrosoft Running a Basic StarPU Application on Microsoft Visual C