[goffice] GOQuad: don't try to change const objects.

[Morten Welinder <mortenw src gnome org>]

commit 3c41c93fd72129621eb329b131f18bdb6e2b190b
Author: Morten Welinder <terra gnome org>
Date:   Sun May 17 19:29:24 2015 -0400

    GOQuad: don't try to change const objects.
    
    That's naughty.

 ChangeLog              |    5 +++++
 NEWS                   |    1 +
 goffice/math/go-quad.c |   31 +++++++++++++++++++------------
 goffice/math/go-quad.h |   28 ++++++++++++++++------------
 4 files changed, 41 insertions(+), 24 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index a04c67f..0a5a4ce 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2015-05-17  Morten Welinder  <terra gnome org>
+
+       * goffice/math/go-quad.c (go_quad_start): Initialize constants via
+       non-const objects.  See bug #749463.
+
 2015-05-16  Morten Welinder  <terra gnome org>
 
        * goffice/graph/gog-theme.c (theme_load_from_uri): Avoid double
diff --git a/NEWS b/NEWS
index a7aaa3c..8a460d9 100644
--- a/NEWS
+++ b/NEWS
@@ -7,6 +7,7 @@ Morten:
        * Fix ABR [#749167]
        * Shield Cairo from image sizes it cannot handle.  [#749274]
        * Plug leak.  [#749395]
+       * Portability problem affecting macs.  [#749463]
 
 --------------------------------------------------------------------------
 goffice 0.10.22:
diff --git a/goffice/math/go-quad.c b/goffice/math/go-quad.c
index fa54e58..7bfe964 100644
--- a/goffice/math/go-quad.c
+++ b/goffice/math/go-quad.c
@@ -31,6 +31,8 @@
  * Note: the compiler should not rearrange expressions.
  */
 
+#define GO_QUAD_IMPL
+
 #include <goffice/goffice-config.h>
 #include <goffice/goffice.h>
 #include <math.h>
@@ -209,37 +211,37 @@ SUFFIX(go_quad_start) (void)
        if (first) {
                first = FALSE;
                SUFFIX(CST) = 1 + SUFFIX(ldexp) (1.0, (DOUBLE_MANT_DIG + 1) / 2);
-               SUFFIX(go_quad_constant8) ((QUAD *)&SUFFIX(go_quad_pi),
+               SUFFIX(go_quad_constant8) (&SUFFIX(go_quad_pi),
                                           pi_hex_digits,
                                           G_N_ELEMENTS (pi_hex_digits),
                                           256.0,
                                           256.0);
 
-               SUFFIX(go_quad_constant8) ((QUAD *)&SUFFIX(go_quad_2pi),
+               SUFFIX(go_quad_constant8) (&SUFFIX(go_quad_2pi),
                                           pi_hex_digits,
                                           G_N_ELEMENTS (pi_hex_digits),
                                           256.0,
                                           512.0);
 
-               SUFFIX(go_quad_constant8) ((QUAD *)&SUFFIX(go_quad_e),
+               SUFFIX(go_quad_constant8) (&SUFFIX(go_quad_e),
                                           e_hex_digits,
                                           G_N_ELEMENTS (e_hex_digits),
                                           256.0,
                                           256.0);
 
-               SUFFIX(go_quad_constant8) ((QUAD *)&SUFFIX(go_quad_ln2),
+               SUFFIX(go_quad_constant8) (&SUFFIX(go_quad_ln2),
                                           ln2_hex_digits,
                                           G_N_ELEMENTS (ln2_hex_digits),
                                           256.0,
                                           1);
 
-               SUFFIX(go_quad_constant8) ((QUAD *)&SUFFIX(go_quad_sqrt2),
+               SUFFIX(go_quad_constant8) (&SUFFIX(go_quad_sqrt2),
                                           sqrt2_hex_digits,
                                           G_N_ELEMENTS (sqrt2_hex_digits),
                                           256.0,
                                           256.0);
 
-               SUFFIX(go_quad_constant8) ((QUAD *)&SUFFIX(go_quad_euler),
+               SUFFIX(go_quad_constant8) (&SUFFIX(go_quad_euler),
                                           euler_hex_digits,
                                           G_N_ELEMENTS (euler_hex_digits),
                                           256.0,
@@ -273,12 +275,17 @@ SUFFIX(go_quad_end) (void *state)
 
 const QUAD SUFFIX(go_quad_zero) = { 0, 0 };
 const QUAD SUFFIX(go_quad_one) = { 1, 0 };
-const QUAD SUFFIX(go_quad_pi);
-const QUAD SUFFIX(go_quad_2pi);
-const QUAD SUFFIX(go_quad_e);
-const QUAD SUFFIX(go_quad_ln2);
-const QUAD SUFFIX(go_quad_sqrt2);
-const QUAD SUFFIX(go_quad_euler);
+/*
+ * The following are non-const so we can initialize them.  However,
+ * from other compilation units there are const.  My reading of C99
+ * Section 6.2.7 says that is allowed.
+ */
+QUAD SUFFIX(go_quad_pi);
+QUAD SUFFIX(go_quad_2pi);
+QUAD SUFFIX(go_quad_e);
+QUAD SUFFIX(go_quad_ln2);
+QUAD SUFFIX(go_quad_sqrt2);
+QUAD SUFFIX(go_quad_euler);
 
 /**
  * go_quad_init: (skip)
diff --git a/goffice/math/go-quad.h b/goffice/math/go-quad.h
index 2f7240f..3f729ce 100644
--- a/goffice/math/go-quad.h
+++ b/goffice/math/go-quad.h
@@ -44,14 +44,18 @@ void go_quad_dot_product (GOQuad *res, const GOQuad *a, const GOQuad *b, int n);
 
 void go_quad_constant8 (GOQuad *res, const guint8 *data, gsize n, double base, double scale);
 
+#ifndef GO_QUAD_IMPL
+#define GO_QUAD_IMPL const
+#endif
+
 GO_VAR_DECL const GOQuad go_quad_zero;
 GO_VAR_DECL const GOQuad go_quad_one;
-GO_VAR_DECL const GOQuad go_quad_pi;
-GO_VAR_DECL const GOQuad go_quad_2pi;
-GO_VAR_DECL const GOQuad go_quad_e;
-GO_VAR_DECL const GOQuad go_quad_ln2;
-GO_VAR_DECL const GOQuad go_quad_sqrt2;
-GO_VAR_DECL const GOQuad go_quad_euler;
+GO_VAR_DECL GO_QUAD_IMPL GOQuad go_quad_pi;
+GO_VAR_DECL GO_QUAD_IMPL GOQuad go_quad_2pi;
+GO_VAR_DECL GO_QUAD_IMPL GOQuad go_quad_e;
+GO_VAR_DECL GO_QUAD_IMPL GOQuad go_quad_ln2;
+GO_VAR_DECL GO_QUAD_IMPL GOQuad go_quad_sqrt2;
+GO_VAR_DECL GO_QUAD_IMPL GOQuad go_quad_euler;
 
 #ifdef GOFFICE_WITH_LONG_DOUBLE
 struct GOQuadl_ {
@@ -96,12 +100,12 @@ void go_quad_constant8l (GOQuadl *res, const guint8 *data, gsize n, long double
 
 GO_VAR_DECL const GOQuadl go_quad_zerol;
 GO_VAR_DECL const GOQuadl go_quad_onel;
-GO_VAR_DECL const GOQuadl go_quad_pil;
-GO_VAR_DECL const GOQuadl go_quad_2pil;
-GO_VAR_DECL const GOQuadl go_quad_el;
-GO_VAR_DECL const GOQuadl go_quad_ln2l;
-GO_VAR_DECL const GOQuadl go_quad_sqrt2l;
-GO_VAR_DECL const GOQuadl go_quad_eulerl;
+GO_VAR_DECL GO_QUAD_IMPL GOQuadl go_quad_pil;
+GO_VAR_DECL GO_QUAD_IMPL GOQuadl go_quad_2pil;
+GO_VAR_DECL GO_QUAD_IMPL GOQuadl go_quad_el;
+GO_VAR_DECL GO_QUAD_IMPL GOQuadl go_quad_ln2l;
+GO_VAR_DECL GO_QUAD_IMPL GOQuadl go_quad_sqrt2l;
+GO_VAR_DECL GO_QUAD_IMPL GOQuadl go_quad_eulerl;
 
 #endif