src: Restore more precise copyright years following "git blame".

* src/asin.c, src/log10.c, src/pow.c, src/tan.c: Use single years instead
  of ranges of years for the copyright notice.

4 files changed, 4 insertions, 4 deletions

diff --git a/src/asin.c b/src/asin.c
index 9b09634..8a1252d 100644
--- a/src/asin.c
+++ b/src/asin.c
@@ -1,6 +1,6 @@
 /* mpc_asin -- arcsine of a complex number.
 
-Copyright (C) 2009-2020 INRIA
+Copyright (C) 2009, 2010, 2011, 2012, 2013, 2014, 2020 INRIA
 
 This file is part of GNU MPC.
 
diff --git a/src/log10.c b/src/log10.c
index 9786cca..5afd4ab 100644
--- a/src/log10.c
+++ b/src/log10.c
@@ -1,6 +1,6 @@
 /* mpc_log10 -- Take the base-10 logarithm of a complex number.
 
-Copyright (C) 2012-2020 INRIA
+Copyright (C) 2012, 2020 INRIA
 
 This file is part of GNU MPC.
 
diff --git a/src/pow.c b/src/pow.c
index 25e2d1b..4fc90ae 100644
--- a/src/pow.c
+++ b/src/pow.c
@@ -1,6 +1,6 @@
 /* mpc_pow -- Raise a complex number to the power of another complex number.
 
-Copyright (C) 2009-2015 INRIA
+Copyright (C) 2009, 2010, 2011, 2012, 2014, 2015, 2016, 2018, 2020 INRIA
 
 This file is part of GNU MPC.
 
diff --git a/src/tan.c b/src/tan.c
index 8bac751..ec26bea 100644
--- a/src/tan.c
+++ b/src/tan.c
@@ -1,6 +1,6 @@
 /* mpc_tan -- tangent of a complex number.
 
-Copyright (C) 2008-2015 INRIA
+Copyright (C) 2008, 2009, 2010, 2011, 2012, 2013, 2015, 2020 INRIA
 
 This file is part of GNU MPC.