Terrific! Now it compiles... but here are some details:
Entering the above command in shell gave me a different set of errors unrelated to
libgretl, i.e. undefined reference to daxpy_undefined reference to dtrmm_. etc...
I'm not a fortran expert but it seemed like those errors were related to fortran
routines. I then did sudo apt-get install gfortran. Then went back to the gretl download
folder. Did ./configure, make, make install. Finally, I again entered the above command
you specified in shell, then it worked:
Model 1: OLS, using observations 1-14Dependent variable: price
             coefficient   std. error   t-ratio   p-value  
--------------------------------------------------------  const       52.3509      37.2855
      1.404    0.1857    sqft         0.138750     0.0187329    7.407    8.20e-06 ***
Mean dependent var   317.4929   S.D. dependent var   88.49816Sum squared resid    18273.57
  S.E. of regression   39.02304R-squared            0.820522   Adjusted R-squared  
0.805565F(1, 12)             54.86051   P-value(F)           8.20e-06Log-likelihood    
 -70.08421   Akaike criterion     144.1684Schwarz criterion    145.4465   Hannan-Quinn    
    144.0501
I'm going to fiddle around and see why the makefiles are not working.
Allin, thank you for your time and help. Much appreciated. Gretl seems like an amazing
piece of software and am excited to start using it.
 
    On Monday, February 15, 2016 2:20 PM, Allin Cottrell <cottrell(a)wfu.edu> wrote:
 
 On Mon, 15 Feb 2016, Salman Khan wrote:
 $ nm /usr/local/lib/libgretl-1.0.so.16.0.0 | grep libgretl_init
 0000000000146040 T libgretl_init 
That looks OK.
 $ cc -vUsing built-in specs. [...] 
Nothing apparently untoward there.
 $ ld -VGNU ld (GNU Binutils for Ubuntu) 2.24 [...] 
Nor there.
So at this point the failure of your compile is a mystery.
Could you try bypassing "make" by running the following shell 
command (in the gretl durectory that contains simple_client.c):
cc -g -O2 -Wall -I/usr/local/include \
  -I/usr/include/libxml2 \
  -I/usr/include/glib-2.0 \
  -I/usr/lib/x86_64-linux-gnu/glib-2.0/include \
  -DPREFIX=\"/usr/local\" -fopenmp \
  simple_client.c -o simple_client -L/usr/local/lib \
  -lgretl-1.0 -lm -lxml2 -lfftw3 -lglib-2.0
Thanks.
Allin Cottrell